The ingot was re-melted and flipped over a few times to ensure uniformity in chemical composition. For TEM measurements, samples were thinned by a mechanical polish followed by an ion milling. According to the XRD measurement results from as-cast and annealed samples Figure 1 , most significant peaks were attributed to the Zr 8 Ni 21 phase, thus indicating that Zr 8 Ni 21 is the dominant phase of the microstructure. However, there were two broad peaks shown on the XRD pattern, e. In the previous paper, EDS measurements collected from different spots were used to evaluate phases of the material [ 11 ].
However, the reason such mixed-phase regions presented was not clear. A composition map of the sample is shown in Figure 2 , where three colors, green, red, and gray, correspond to Zr, Ni, and the SEM secondary electron image SEI , respectively. Occasional inclusions of ZrO 2 were also found in the alloy Spot D. These ZrO 2 inclusions appear to be much lower in average atomic weight, showing darker contrast in the SEM backscattering electron image Figure 1 a in Reference [ 11 ].
Comparison between the EDS measured Ni-Zr composition ratio and the composition from the corresponding stoichiometric phase. Further confirmation of the phases came from the crystallographic analysis of the phases by electron diffraction from the TEM sample. For example, in Figure 3 , areas A, B, and C are electron-transparent thin areas and are located in a Ni-rich region, a major Zr 8 Ni 21 phase region, and a Zr-rich region, respectively. Typical bright field TEM images taken from the thin areas are shown in the insets of Figure 3. High-resolution TEM images a , c and e and corresponding selected area diffraction patterns b , d and f obtained from areas A, B and C in Figure 2 , respectively.
With the help of single crystal diffraction simulations and indexing red circles , the structures of areas A, B and C are identified as Zr 2 Ni 7 , Zr 8 Ni 21 and Zr 7 Ni 10 , respectively. Such phase distribution in this Zr-Ni alloy material can be well explained by the Zr-Ni phase diagram with the assumption that annealing of the alloy was not sufficient to eliminate the cast structure otherwise a single-phase Zr 8 Ni 21 structure would be observed Figure 5.
At this point, the peritectic reaction between solid Zr 2 Ni 7 and liquid is attempted; the reaction results in the formation of the Zr 8 Ni 21 phase that envelops the Zr 2 Ni 7 dendrites. The peritectic reaction is diffusion-limited, and the continuous cooling may not allow enough time for the reaction to be completed. Judging from its average stoichiometry Ni-Zr phase diagram showing formation of the observed phases during continuous cooling of the Zr 8 Ni 21 melt. The image shows a high density of planar defects according to SAED patterns.
Figure 6 b,c indicate the defect planes are of Zr 2 Ni 7. A SAED pattern forms a region with a lower density of defects in Figure 6 b and shows that it can be indexed as Zr 2 Ni 7 in the  zone axis, which is confirmed by comparing it with the simulated  patterns, Figure 6 e, using a structural model of Eshelman et al.
However, SAED from regions with a higher density of defects, Figure 6 b, shows a dense distribution of reflection and intensity streaks along the 0 kl rows. The reason for the copious formation of these rotational domains is the pseudo-hexagonal nature of the monoclinic Zr 2 Ni 7 structure. Figure 7 a shows a projection of the structure in the  direction; the structure can be described as a stacking of two types of layers with compositions of Ni 2 Zr and Ni 3. The structure can be subdivided into two very similar blocks consisting of two Ni 2 Zr and one Ni 3 layers.
Figure 7 b,c show projections of the layers with an outlined two-dimensional unit cell, from which the pseudo-hexagonal close-packed arrangement of atoms is evident. However, the Ni 2 Zr layers, which have identical structural projections, are subdivided into two variants differentiated by the deviation of Zr and Ni from the medial plane: L1 and L4 with Zr upward and L3 and L6 with Ni upward Figure 7 a. In the Zr 2 Ni 7 structure, the layers within a block are in the same CP position e. Mistakes in the selection of CP position e. SAED patterns in Figure 6 b,c show a significant difference in the intensity of 00 l reflections with odd l ; in some samples' locations, the 00 l reflections are completely lacking.
In the analysis by Parthe and Lemair [ 33 ], by allowing small changes in the point positions of less than 0. In this structure, Blocks 1 and 2 are identical Figure 8 a,b , but the diffraction is lacking odd 00 l , or become a new structure Figure 8 c,d. From the TEM study of the fine structure of the Zr 2 Ni 7 phase, it is concluded that the crystallite size of this phase is very small.
However, it is possible for several peaks to overlap as the crystallite size becomes smaller. As the crystallite size reduces, the XRD peaks become broader and start to overlap. When the crystallite size is below 5 nm, two board peaks centered at around We therefore conclude that those two broad peaks observed in the XRD pattern of the Zr 8 Ni 21 alloy are from the nano-sized Zr 2 Ni 7 phase formed by planar defects.
The reflections from the Zr 2 Ni 7 phase are labeled at the bottom. Peak positions and intensities are from PDF This highly defective structure of Zr 2 Ni 7 contributes to those two broad peaks observed in XRD analysis. Kwo Young and Jean Nei prepared the ingot sample. Leonid A. All the authors made significant contributions to the writing of this manuscript. Dionysiou , G. Marin , J. Santamaria , K. Yeung , T. Aminabhavi , D. Kondarides , T. Hoare , U. View Editorial Board. Submit Your Paper Enter your login details below.
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Peiyu Hou Jiangmei Yin Its very existence is remarkable, thanks to the delicate balance between interparticle potential and entropy. The phase behaviors of liquids and liquid-like matter, especially when driven out of equilibrium by extreme conditions, are exceptionally rich. Accordingly, the physics of liquids have attracted much attention in the recent decades. In addition, numerous soft and biological materials of amazing far-from-equilibrium complexity seem to share many intriguing features of liquids. Therefore, quantitative descriptions of the structure and dynamics of liquids and liquid-like matter will likely impact a wide range of disciplines in physics, chemistry, and materials science and engineering.
This session will focus on the forefront of the research on liquids, from fresh theoretical treatments and computations to cutting-edge experimental techniques. Machine learning approaches offer promising methods to accelerate the discovery of new materials with tunable properties. This session will focus on machine learning approaches to design novel bulk metallic glasses and other glass-forming materials. To date, the materials community has tested the glass-forming ability of only an extremely small fraction of the possible metal alloys.
Coupling high-throughput fabrication and characterization techniques with machine learning approaches will enable researchers to explore an unprecedentedly large composition space of metallic glasses. This focus session seeks abstracts from interdisciplinary researchers in physics, materials science and engineering covering experimental and computational design of new glass-formers with optimized properties, structure-property relationships, and high-throughput fabrication and characterization techniques.
We believe that this focus session will catalyze new collaborations aimed at the discovery of new metallic glasses. Organizers: Corey S. O'Hern Yale University, corey. This focus session builds on recent progress on pattern formation in granular systems, ranging from planetary surface and subsurface to active soft matter. This session can bring focus to this area in which there has been substantial progress on fundamental modeling and experiments focused on an individual component of the rich fluid driven pattern formation in these systems.
But the relationships if any among these different systems remain unclear and are actively being examined by several groups. This focus session seeks to attract contributions from all of these fields and more to expose and, hopefully, clarify these relationships. Organizers: David K. Campbell Boston University, dkcampbe bu. Physical manipulation of single biomolecules, including DNA, RNA, proteins, and macromolecular filaments, have found many powerful applications in studying biophysical properties and processes.
Techniques include optical tweezers, magnetic tweezers, atomic force microscope cantilevers, and hydrodynamic flow. Applications have included studies that have shed light on fundamentals of biopolymer mechanics, protein-DNA interactions, protein and RNA folding, and molecular motor function. This focus session will explore traditional techniques and applications of single molecule manipulation techniques and developments of new approaches and applications. Information needed by all cells to survive and proliferate is encoded in the sequence of nucleotides in genomic DNA.
In eukaryotes, DNA is packaged into chromatin — a complex multi-scale structure which ensures that all chromosomes into the tight of the cell nucleus. However, DNA in this packaged state must either remain accessible to various regulatory proteins such as transcription factors which turn genes on and off or be made accessible rapidly and robustly in response to various challenges facing the cell throughout its life cycle.
This dilemma of packaging and accessibility has recently attracted a lot of attention from the biological physics community, with methods from polymer physics, statistical mechanics, and condensed matter physics being applied to understand DNA folding and dynamics, protein-DNA interactions, and chromatin structure and function. This session will focus on the latest developments in this rapidly advancing field, bringing together experimental and theoretical scientists in the fields of chromatin, DNA, and protein-DNA recognition.
Organizers: Alexandre V. Morozov Rutgers University , Gary D. Stormo Washington University, stormo wustl. Proteins and nucleic acids play important roles in many biological processes. Understanding and predicting their structures, dynamics, interactions, and energetics are highly valuable to uncover the mechanisms of these processes and to design therapeutic interventions.
The physics community is continuing to provide key contributions to this field. We deliberately give a general title for the session to attract broad audience DBIO, chemical physics, computational physics, and optics. The first invited speaker, Mike Gilson, is a world-renowned scientist studying the physical basis of molecular interactions e. Their talks will be interesting to DBIO and physicists on physical chemistry, computational chemistry and optics. Both co-organizers are women, and will strongly encourage minorities and women to give contributed talks.
This focus session will explore the physics of cytoskeletal systems on length scales ranging from the molecular to the cellular, and across disciplines, bringing together approaches ranging from structural biology to measurements of network dynamics to modeling in order to reveal the physical mechanisms of cellular behavior. We will focus on work that connects molecular level features with higher-level properties of cytoskeletal filaments and their assemblies. Our emphasis will include how such properties enable and control cellular and tissue function, and how stresses and other signals are transmitted and sensed in such a dynamic, stochastic environment.
This session will convene outstanding speakers, who will talk about biomaterials seen from a physics point of view, with specific attention to the structure, the function, and the relationship between structure and function, in both natural biomaterials and synthetic materials inspired by nature. Buehler and Kats are a theorist and an experimentalist, both are excellent speakers and world leaders in biomaterials.
The session will highlight how synthetic biological engineering of cells and molecules can provide research tools for biological physics, to interrogate biological systems at all scales by delivering precise stimuli, obtaining quantitative readouts, performing parameter scans, thereby discovering quantitative principles of biological organization and function. The universe of bacteria and other microbes that live in concert with their host or environment is often called the microbiome. Interest in the physical properties of microbiome is as old as the field of microbiology itself.
Back in the s, Antoine van Leeuwenhoek first discovered that microorganisms living on and in his body, vary a lot in their shape and sizes, suggesting the first hint of a complex microbiome. Recent advances in imaging and sequencing technologies are producing a revolution in the microbiome field. This revolution presents enormous opportunities for physics and physicists to advance this incredibly exciting field by revealing functional relationships connecting the biogeography and organizational principles of microbiome to the health or wellbeing of its hosts or environment.
Intracellular transport describes the continued and dynamic movement of materials in cells. Importantly, dysfunctions in this process are linked to diseases including neurodegeneration. Intracellular transport cannot be accomplished by passive diffusion alone. Instead, cells utilize protein machines molecular motors to actively transport materials along the cytoskeleton. This Focus Session will bring together experimentalists and theorists working to dissect the physical principles of transport, particularly under complex conditions such as those that occur in cells.
Information theory and machine learning methods have been used in science largely for classification purposes. Here we will explore different attempts to use them to predict dynamics of complex often biological systems from data, and to gain physical understanding of the system in the process. Electric fields are surprisingly ubiquitous in cellular systems from membrane potentials of firing neurons to native electric fields of healing wounds. Many biological techniques controlling cell behavior such as brain stimulation and electroporation utilize electric fields. While the biological processes are very distinct from neuroscience to wound healing, this focus session will concentrate on the unifying physics of cell responses to electric fields from molecular scales to cellular scales, including tissue scale responses to electric fields.
Robots are moving from the factory floor and into our lives autonomous cars, homecare assistants, search and rescue devices, etc. We propose that interaction of researchers studying dynamical systems, soft materials, and living systems can help discover principles that will allow physical robotic devices to interact with the real world in qualitatively different ways than they do now. And we propose that a Focus session at the APS March meeting that brings together leaders in this emerging area most of whom are not physicists will demonstrate the need for a physics of robotics and reveal interesting problems at the interface of nonlinear dynamics, soft matter, control, and biology.
Goldman Georgia Tech, dgoldman3 gatech. It is well known that oscillations and the formation of spatial patterns are intimately connected — for example, similar activator-inhibitor networks can drive both behaviors, and oscillations can drive traveling waves that lead to intricate patterns. This session will bring together talks describing new research on oscillatory pattern formation in organisms ranging from bacteria to zebrafish.
It will thereby introduce March Meeting attendees to some of the latest findings on a variety of important model systems, while also allowing them to see emerging commonalities between the pattern formation mechanisms in these different examples. Recent advances in imaging and sequencing methodologies allow for the first time the visualization and quantification of the events driving embryonic development.
These experimental and theoretical studies are revealing novel physical principles of regulation of biological systems and they will be the focus of the Session. The field of Morphogenesis lies at the intersection between physics, biology and engineering. Many recent activities have focused on understanding how biology has devised elaborated strategies for regulating pattern formation and mechanical forces in both space and time.
Morphogenesis has also inspired scientists to design shape-programmable stimuli-responsive matter. This session aims at bringing together researchers from diverse backgrounds to forge new interdisciplinary connections. This session is designed to showcase recent advances in the application of physical methods and in the formulation of physical principles to understanding brain structure and dynamics. It will also highlight some of the outstanding problems whose solutions will be advanced by application of physics. We expect that the opportunities explored in this session will stimulate more inputs from physicists to this interdisciplinary field.
The dynamics of populations represent an exciting frontier for physicists to understand the emergent structure that results from the interactions of individuals within a population or species within a community. This focus session will bring together experimental and theoretical approaches to develop a unified understanding of the evolutionary and ecological dynamics of populations.
The focus of this session will be on quantifying evolutionary dynamics via state of the art experiments and modeling. The era of sequencing enabled new precision measurements, and now we have abundant data on the evolution of microbes and viruses. These organisms have large population sizes and short generation times, both of which allow us to probe fundamentals of evolutionary biology. However, many unknowns remain.
In the case of pathogens, there are important open questions regarding the evolution of drug resistance. Also, the relationship between rates of genomic evolution and organismal adaptation is at best uncertain. We do not know what sets the size of the genomes, what determines the numbers of genes in genomes, what is the role of horizontal gene transfer on the genome evolution, what determines the temporal dynamics etc. Our goal is to show some of the recent precision measurements and theoretical predictions in evolutionary biology. Living systems organize in large scale structures and dynamics that are essential to life.
Synthetic or bio-inspired active matter emulates similar behavior with model building blocks. This session focuses on the recent progress to understand, control and design self-organization in biology and active matter. It aims at bridging the biophysics and soft matter community and provides a broader scope to our understanding of non-equilibrium systems. The aim of the symposium is to bring together world-leading experts on structure and reactivity of gas phase clusters and to discuss future directions in this field.
The role of gas phase clusters as model systems for related condensed phase systems will be emphasized. This symposium will bring together experts in the field of molecular magnetism to define current challenges in this field, examine conditions under which their behaviors transform from classical to quantum, and determine how coherent spin effects arise and break down.
In addition to possible qubit and quantum-sensor design, talks aimed at rigorous understanding of field-photon- or electron- induced control or interrogation of such systems in chemical, physical and aqueous environs are encouraged as are talks that investigate the role of spin physics in similar naturally occurring functional inorganic molecules. The aim of the symposium is to bring together world experts on state-of-the-art computational and experimental techniques to discuss i the key role played by the interplay of experiment and theory in spectroscopy gas-phase studies, ii the target accuracy and challenges to be aced by computations when aiming at reproducing and predicting experimental results, and iii future directions to further reduce the gap between theory and experiment.
The accurate simulation of many electronic phenomena in the condensed phase requires tools with predictive power beyond that of DFT. This Focus Session will bring together researchers working on such techniques for systems with explicit periodicity. Represented approaches will include those based on many-electron wavefunctions, Green's functions, quantum Monte Carlo, and embedding formalisms.
Emphasis will be placed on a comparison of the strengths and weaknesses of various methods and collaborative opportunities to advance the field of condensed-phase electronic structure. This symposium will bring together experts working in the field of synthesis, characterization, and modeling of hierarchical systems to discuss recent advances and future research directions.
Atomic, molecular, and optical systems offer new settings to explore localization - both in disordered settings with analogs to solid state systems, as well as in novel geometries such as quasiperiodic lattices. Intriguing transport, entanglement, and many-body effects have been realized as new probes are being constructed. For example, progress in building atomic gas microscopes now allows detailed microscopic studies of localization in time evolution.
The control and isolation of AMO systems also make them particularly appealing for exploring concepts surrounding many-body localization, in which there is an interplay between disorder and interactions. Topological quantum phases of electrons such as quantum Hall states, topological insulators and topological semimetals have been major topics in condensed matter physics with important implications for metrology, low-dissipation electronics, quantum computing and other device applications.
By combining mechanical, optical, and atomic elements, one creates systems with novel properties which can be used for answering fundamental questions and developing new technology. New ideas continue to emerge about coupling systems in ways which make the most of their characteristics such as the long coherence times of photons, or the large coupling matrix elements in mechanical systems.
These hybrid systems are becoming useful for metrology, and continue to erode the dividing line between the microscopic and the macroscopic. High precision quantum many-body platforms provide new environments for studying out-of-equilibrium physics. The possibility to control the range of interactions, from short-range for cold atoms to long-range for molecules, Rydberg gases, and trapped ions, allow one for instance to study speed limits on the spread of correlations after a quantum quench.
Because of the combination of long coherence times and highly accurate tools such as quantum gas microscopy available in these systems, non-trivial dynamics can be observed in up to 10th order correlators, and even entanglement can be measured. Integrability and disorder can be tuned and initial state preparation is highly controlled.
Università di Pisa: corso di laurea in MATERIALS AND NANOTECHNOLOGY
Thus one can explore evolution from excited states as well as under periodic driving, allowing access to a range of problems ranging from the dynamics of many-body localized systems to time crystals and other Floquet phenomena. This session will bridge AMO, condensed matter, quantum information, and non-equilibrium statistical mechanics. We now have hundreds of experimental quantum simulators worldwide running on a tremendous variety of architectures including ultracold atoms in optical lattices, Rydberg gases, trapped ions, ultracold molecules, exciton-polariton systems, coupled cavity arrays, and Josephson-Junction-based superconducting nano-electro-mechanical systems.
Such simulators have led to significant advances in our understanding of quantum many-body phases and near-equilibrium phenomena. Beyond work done so far in quantum optics and other contexts, these simulators offer us a new opportunity to address deep unanswered questions in open quantum systems far from equilibrium. At the same time, quantum simulation methods on classical computers, including matrix product density operators and quantum trajectories-based methods, have opened up the opportunity to explore specific dynamical open system models both within and outside the Markov and secular approximations.
They will also allow us to explore new regimes of quantum mechanics, quantum measurement, and quantum technology. The experimental and computational study of quantum systems consisting of a relatively small number of particles enjoys a renewed interest in the broad community thanks to the recent theoretical and experimental developments in achieving unprecedented accuracy for few-particle systems.
A complete understanding of all these subtle effects makes it necessary to massively go beyond the common approximations used to describe atoms and molecules and opens up directions for building new physical theories even beyond the Standard Model. The purpose of this focus session is to survey recent activity in the field that is related to the following areas: Precision spectroscopy of small atoms and molecules; Molecular quantum mechanics beyond the Born—Oppenheimer approximation; Non-adiabatic models for molecular systems; Relativistic and quantum electrodynamics computations for molecules; High-level quantum chemistry methods e.
There has been explosive growth in the study of topological insulators in which the combined effects of the spin-orbit coupling and time-reversal symmetry yield a bulk energy gap with novel gapless surface states that are robust against scattering. Moreover, the field has expanded in scope to include topological phases more complex materials such as Kondo systems, magnetic materials, and complex heterostructures capable of harboring exotic topologically nontrivial state of quantum matter.
The observation of theoretical predictions depends greatly on sample quality and there remain significant challenges in identifying and synthesizing the underlying materials that have properties amenable to the study of the bulk, surface and interface states of interest. This topic will focus on fundamental advances in the synthesis, characterization and modeling of candidate topological materials in various forms including single crystals, exfoliated and epitaxial thin films and heterostructures, and nanowires and nanoribbons, in addition to theoretical studies that illuminate the synthesis effort and identify new candidate materials.
Organizers: Lu Li University of Michigan, luli umich. The field of topological semimetals has developed dramatically over the past few years. After the initial prediction and discovery of Dirac and Weyl semimetals — materials whose low energy excitations can be described by the Dirac or Weyl equation of high-energy physics — the field has now expanded to include new low-energy excitations not possible in a high-energy setting.
Semimetals with different degeneracy at crossing points or lines have been predicted. Transport theories and effects have been predicted and proposed in order to measure a small subset of the topological characteristics of the semimetals such as Chern numbers. Furthermore, semimetals whose existence is guaranteed by filling constraints derived from the presence of certain orbitals at certain points in specific lattices have also been mentioned in the literature.
Distinct from conventional low carrier density systems, Dirac, Weyl and other semimetals are expected to possess exotic properties due to the nontrivial topologies of their electronic wave functions. A subset of the novel properties predicted include Berry phase contributions to transport properties, chiral anomaly, quantized nonlinear transport under circularly polarized light, protected Fermi arc surface states, suppressed scattering, optical control of topology, landau level spectroscopy, superconductivity, and non-local transport.
While promising candidate materials exist for many but certainly not all of the topological semimetals, many phenomena have yet to be clearly resolved. This focus topic aims to explore Dirac, Weyl and other new semimetals and the novel phenomena associated with them.
We solicit contributions on predictions, new materials synthesis and characterization, new phenomena in topological semimetals, as well as studies on both conventional and unconventional semimetals, both in the bulk and on the surfaces of samples that accentuate the non-trivial topological character of the new semimetals. Organizers: Dmytro Pesin University of Utah, d. Topological superconductors are superconductors characterized by topological invariants associated with the band structure of the Bogoliubov quasiparticles.
They have been a focus of significant experimental and theoretical efforts in view of their relevance to fundamental physical and mathematical concepts, and potential for quantum computation. Along with the search for bulk materials candidates, there has been much recent progress in studies of atomically thin films, artificially engineered structures, and the surfaces of bulk materials. This Focus Topic will cover topological superconductivity and the closely related non-centrosymmetric superconductivity in new experimental settings involving transition metal dichalcogenides, topological insulators, Weyl semi-metals, FeSe-based systems, graphene, engineered heterostructures, semiconducting nanowires, atomic chains and Shiba states, junctions with ferromagnets, quantum Hall states, and driven systems and Floquet states.
This Focus Topic will also cover the new understanding of bulk materials candidates such as Sr2RuO4 and the emerging opportunities in platforms such as twisted bilayers of 2D materials, and advances in strategies for quantum information processing using topological superconductivity. Organizers: Arun Bansil Northeastern University, ar.
Impurities and native defects profoundly affect the electronic and optical properties of semiconductor materials. Impurity incorporation is often a necessary step for tuning the electrical properties in semiconductors. Defects control carrier concentration, mobility, lifetime, and recombination; they are also responsible for the mass-transport processes involved in the migration, diffusion, and precipitation of impurities and host atoms.
Controlling the presence of impurities and defects is a critical factor in semiconductor engineering, and has enabled the remarkable development of Si-based electronics, GaN based blue light-emitting diodes and lasers, semiconducting oxides for transparent conducting displays, and the promise of next-generation sensors and computing based on defects like the NV center in diamond. The fundamental understanding, characterization and control of defects and impurities will also be essential for developing new devices, such as those based on novel wide-band gap semiconductors, spintronic materials, and low dimensional structures.
The physics of dopants and defects in semiconductors, from the bulk to the nanoscale and including surfaces and interfaces, is the subject of this focus topic. Abstracts on experimental, computational and theoretical investigations are solicited in areas of interest that include: the electronic, structural, optical, and magnetic properties of impurities and defects in elemental and compound semiconductors; wide band-gap materials such as diamond, aluminum nitride, and gallium oxide; single-photon emitters including NV centers and their analogues; defects in two-dimensional materials including phosphorene, h-BN, transition metal dichalcogenides, 2D ferromagnets, and MXenes; and the emerging organic-inorganic hybrid perovskite solar cell materials are of interest.
Abstracts on specific materials challenges involving defects, e. Organizers: Cyrus Dreyer Rutgers University, cedreyer physics. Complex oxides can exhibit a rich variety of order parameters, such as polarization, strain, charge and orbital magnetization degrees of freedom. Their ordering phenomena give rise to a vast range of functional properties including ferroelectricity, polarity, pyroelectricity, electrocaloricity, magnetoelectricity, multiferroicity, metal-insulator transitions and defect- related properties, which are the principal topics of interest for this symposium.
Understanding and harnessing these functional properties in view of new applications is a major challenge in our field:. Contributions on breakthroughs and progress in the theory, synthesis, characterization, and device implementations in these and other related topics are highly encouraged. Organizers: Julia Mundy Harvard, mundy fas. Organometallic halide perovskites have recently caused a surge of interest in their optoelectronic properties and applications due to their remarkable performance as semiconductor light absorbers in solar cells.
As a new class of semiconductors, these materials are interesting not only because of the hybrid organic-inorganic structure, but also for their superior properties such as high defect tolerance, strong optical absorption, low recombination rate, ambipolar charge transport, and tunable physical properties. Rapid progress has been made in the demonstration of photoelectronic perovskite devices for photovoltaics, light emission, lasing and photodetection.
However, the underlying physics of many unusual properties remains elusive, such as the hysteretic current-voltage relationships, low recombination rate, long spin lifetime and ferroelectric behavior. The practical use of these hybrid perovskite calls for more in-depth understanding of their fundamental properties and versatile strategies to tune and optimize the materials properties. In this Focus Topic we expect contributions on broadly-defined experimental and modeling studies of the optical, electronic, structural and defect properties of the organometallic halide perovskites.
Advancements in materials engineering and the development of practical applications are also encouraged. Berry nrel. Fe-based superconductors FeSCs continue to fascinate the materials and condensed matter physics communities as we move into a new decade of their study. While the field started from the iron pnictides, new efforts have increasingly been directed towards the iron chalcogenides. Recent advances in the synthesis and control of the FeSCs are giving us renewed hope for even higher superconducting transition temperatures.
At the same time, considerable progress is being made in the understanding of these materials, including the bad-metal normal state and the degree of electron-electron correlations, the order and excitations of the various electronic degrees of freedom spin, orbital, charge and nematic , the role of quantum criticality in the phase diagram, and the amplitude and structure of the multi-orbital superconducting pairing. In addition, there is progress in understanding the unifying principles that may optimize superconductivity of the FeSCs and connect them with other unconventional superconductors such as the cuprates, heavy fermions and organic charge-transfer salts.
This focus topic will cover the pertinent recent developments in the materials growth, experimental measurements and theoretical understandings, and survey the potential for discovering new superconducting systems with still higher transition temperatures. Reduced dimensionality and confinement often lead to magnetic states and spin behaviors that are markedly different from those observed in bulk materials.
This Focus Topic explores advances in magnetic nanostructures, the novel properties that arise in magnetic materials at the nanoscale, and the advanced characterization tools required for understanding these properties. Magnetic nanostructures of interest include thin films, multilayers, superlattices, nanoparticles, nanowires, nanorings, 3D nanostructures, nanocomposite materials, hybrid nanostructures, magnetic point contacts, and self-assembled, as well as patterned, magnetic arrays.
Sessions will include talks on the methods used to synthesize such nanostructures, the variety of materials used, and the latest original theoretical, experimental, and technological advances. Phenomena and properties of interest include magnetization dynamics and reversal, singular magnetic textures, magnonics, magnetic interactions, magnetic quantum confinement, spin tunneling and spin crossover, proximity and structural disorder effects, strain effects, microwave resonance and microwave assisted reversal, magnetic anisotropy, and thermal and quantum fluctuations.
The emergence of novel states of matter, arising from the intricate coupling of electronic and lattice degrees of freedom, is a unique feature in strongly correlated electron systems. This Focus Topic explores the nature of such ordered states observed in bulk compounds of transition metal oxides; it will provide a forum for discussion of recent developments in theory, simulation, synthesis, and characterization, with the aim of covering basic aspects and identifying future key directions in bulk oxides.
Associated with this complexity is a tendency for new forms of order, such as the formation of stripes, ferroic states, spin-orbit entangled states or phase separation. An additional focus of this session is on how competing interactions result in spatial correlations over multiple length scales, giving rise to enhanced electronic and magnetic susceptibilities and responses to external stimuli.
The intricate interactions between electronic and structural degrees of freedom make magnetism in complex oxides an intriguing field of research. Specifically, in thin films and heterostructures of magnetic oxides emergent phenomena can arise from the competition and cooperation of strain, lattice symmetry, orientation, size, and interfacial effects.
These tuning factors support a wide variety of interfacial phenomena such as charge transfer, orbital reconstruction, proximity effects, and modifications to local atomic structure. Novel electronic and magnetic ground states at oxide interfaces thus generates exciting new prospects both for discovery of fundamental physics and the development of technological applications.
This Focus Topic is dedicated to progress in the knowledge, methodologies, and tools required to advance the field of magnetism in oxide thin films, heterostructures, superlattices, and nanostructures. Synthesis, characterization, theory, and novel device physics are emphasized. Specific areas of interest include, but are not limited to, growth of oxide thin films and heterostructures, control of their magnetic properties and ordering, magnetotransport, magnetic behavior in strongly correlated systems, strong spin-orbit coupling effects, dilute magnetism, magnetoelectric phenomena, coupling of atomic and magnetic structures, and recent developments in theoretical prediction and materials-by-design approaches.
Advances in experimental techniques to probe and image magnetic order and transitions in complex oxide thin films including scanning probes, optical, electron, neutron, and synchrotron-based techniques are also emphasized. As a rule of thumb, if magnetism plays a key role in the investigation, then the talk is appropriate for this focus topic.