scholarly journals Topological Magnets: Functions Based on Berry Phase and Multipoles

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Satoru Nakatsuji ◽  
Ryotaro Arita
Keyword(s):  
Berry Phase ◽  
Technological Development ◽  
Nodal Point ◽  
Real Space ◽  
Nodal Line ◽  
Annual Review ◽  
Publication Date ◽  
Berry Curvature ◽  
Magneto Optical Effect ◽  
Magnetic Spin

Macroscopic responses of magnets are often governed by magnetization and, thus, have been restricted to ferromagnets. However, such responses are strikingly large in the newly developed topological magnets, breaking the conventional scaling with magnetization. Taking the recently discovered antiferromagnetic (AF) Weyl semimetals as a prime example, we highlight the two central ingredients driving the significant macroscopic responses: the Berry curvature enhanced because of nontrivial band topology in momentum space, and the cluster magnetic multipoles in real space. The combination of large Berry curvature and multipole enables large macroscopic responses such as the anomalous Hall and Nernst effects, the magneto-optical effect, and the novel magnetic spin Hall effect in antiferromagnets with negligible net magnetization, but also allows us to manipulate these effects by electrical means. Furthermore, nodal-point and nodal-line semimetallic states in ferromagnets may provide the strongly enhanced Berry curvature near the Fermi energy, leading to large responses beyond the conventional magnetization scaling. These significant properties and functions of the topological magnets lay the foundation for future technological development such as spintronics and thermoelectric technology. Expected final online publication date for the Annual Review of Condensed Matter Physics, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Measure Transportation and Statistical Decision Theory

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Marc Hallin
Keyword(s):  
Real Space ◽  
Statistical Decision Theory ◽  
Annual Review ◽  
Publication Date ◽  
Var Models ◽  
Statistical Decision ◽  
Distribution Free ◽  
The Real ◽  
Inference Problems ◽  
New Concepts

Unlike the real line, the real space, in dimension d ≥ 2, is not canonically ordered. As a consequence, extending to a multivariate context fundamental univariate statistical tools such as quantiles, signs, and ranks is anything but obvious. Tentative definitions have been proposed in the literature but do not enjoy the basic properties (e.g., distribution-freeness of ranks, their independence with respect to the order statistic, their independence with respect to signs) they are expected to satisfy. Based on measure transportation ideas, new concepts of distribution and quantile functions, ranks, and signs have been proposed recently that, unlike previous attempts, do satisfy these properties. These ranks, signs, and quantiles have been used, quite successfully, in several inference problems and have triggered, in a short span of time, a number of applications: fully distribution-free testing for multiple-output regression, MANOVA, and VAR models; R-estimation for VARMA parameters; distribution-free testing for vector independence; multiple-output quantile regression; nonlinear independent component analysis; and so on. Expected final online publication date for the Annual Review of Statistics, Volume 9 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Organic Isotopologue Frontier

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Alexis Gilbert
Keyword(s):  
Organic Molecules ◽  
Technological Development ◽  
Isotope Composition ◽  
Measurement Techniques ◽  
Isotope Analysis ◽  
Annual Review ◽  
Publication Date ◽  
Stable Isotope Composition ◽  
New Information ◽  
Technological Developments

Organic molecules are key components of the Earth-life system. Their stable isotope composition provides information on various problems such as past climate, energy resources, or the synthesis of prebiotically relevant molecules on Earth and elsewhere. Organic molecules are made of isotopologues, molecules differing in the number and/or position of isotope substitution. Recent years have witnessed a boom in technological development dedicated to isotopologue measurement, leading to an unprecedented degree of information regarding organic (bio)synthesis. While applications in Earth and planetary sciences has been limited so far to simple hydrocarbons, typically methane, isotopologue proxies are expected to rapidly emerge in biogeochemistry, providing new types of environmental and biological tracers. This review describes principles and measurement techniques, as well as present and potential biogeochemical applications. ▪ Stable isotopes of organic molecules are widely used in biogeo-chemistry. ▪ Isotope analysis at the intramolecular level is expected to provide new information on the origin of molecules. ▪ Recent technological developments unlocked the potential of intramolecular isotope analysis, providing new proxies in biogeochemistry and new opportunities to clarify questions related to Earth and planetary sciences. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 49 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Surface Chemistry of Metal Phosphide Nanocrystals

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Forrest W. Eagle ◽  
Ricardo A. Rivera-Maldonado ◽  
Brandi M. Cossairt
Keyword(s):  
Surface Chemistry ◽  
Materials Science ◽  
Technological Development ◽  
Annual Review ◽  
Publication Date ◽  
Full Potential ◽  
Science And Engineering ◽  
Metal Phosphide ◽  
Metal Phosphides ◽  
Materials Science And Engineering

Semiconducting and metallic metal phosphide nanocrystals have gained increased attention in the materials science and engineering community due to their demonstrated and theoretical promise in both emissive and catalytic applications. Central to realizing the full potential of nanoscale metal phosphides is a thorough understanding of their surfaces and how surface chemistry impacts their function. In this review, we document what is known about the surface chemistry of metal phosphide nanocrystals, including both as synthesized and postsynthetically modified species, and draw a connection between surface chemistry and functional properties. This survey is intended to provide a comprehensive view of metal phosphide nanocrystal surface chemistry and how it differs across the families of phosphide materials. A clear distinction emerges between the semiconducting and metallic phosphides from both a synthetic and applied standpoint. We seek to expose key knowledge gaps and targets for further scientific and technological development. Expected final online publication date for the Annual Review of Materials Science, Volume 51 is August 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Interface-induced sign reversal of the anomalous Hall effect in magnetic topological insulator heterostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fei Wang ◽  
Xuepeng Wang ◽  
Yi-Fan Zhao ◽  
Di Xiao ◽  
Ling-Jie Zhou ◽  
...  
Keyword(s):  
Hall Effect ◽  
Electric Fields ◽  
First Principles ◽  
Berry Phase ◽  
Condensed Matter ◽  
Anomalous Hall Effect ◽  
First Principles Calculations ◽  
Sign Reversal ◽  
Berry Curvature ◽  
Topological Materials

AbstractThe Berry phase picture provides important insights into the electronic properties of condensed matter systems. The intrinsic anomalous Hall (AH) effect can be understood as the consequence of non-zero Berry curvature in momentum space. Here, we fabricate TI/magnetic TI heterostructures and find that the sign of the AH effect in the magnetic TI layer can be changed from being positive to negative with increasing the thickness of the top TI layer. Our first-principles calculations show that the built-in electric fields at the TI/magnetic TI interface influence the band structure of the magnetic TI layer, and thus lead to a reconstruction of the Berry curvature in the heterostructure samples. Based on the interface-induced AH effect with a negative sign in TI/V-doped TI bilayer structures, we create an artificial “topological Hall effect”-like feature in the Hall trace of the V-doped TI/TI/Cr-doped TI sandwich heterostructures. Our study provides a new route to create the Berry curvature change in magnetic topological materials that may lead to potential technological applications.

scholarly journals 2D‐Berry‐Curvature‐Driven Large Anomalous Hall Effect in Layered Topological Nodal‐Line MnAlGe

2021 ◽  
pp. 2006301
Author(s):  
Satya N. Guin ◽  
Qiunan Xu ◽  
Nitesh Kumar ◽  
Hsiang‐Hsi Kung ◽  
Sydney Dufresne ◽  
...  
Keyword(s):  
Hall Effect ◽  
Anomalous Hall Effect ◽  
Nodal Line ◽  
Berry Curvature ◽  
Curvature Driven

Endogenous Retroviruses Drive Resistance and Promotion of Exogenous Retroviral Homologs

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Elliott S. Chiu ◽  
Sue VandeWoude
Keyword(s):  
Immune Modulation ◽  
Viral Infections ◽  
Viral Evolution ◽  
Endogenous Retroviruses ◽  
Annual Review ◽  
Publication Date ◽  
Biological Functions ◽  
Self Tolerance ◽  
Vertebrate Hosts ◽  
Insight Into

Endogenous retroviruses (ERVs) serve as markers of ancient viral infections and provide invaluable insight into host and viral evolution. ERVs have been exapted to assist in performing basic biological functions, including placentation, immune modulation, and oncogenesis. A subset of ERVs share high nucleotide similarity to circulating horizontally transmitted exogenous retrovirus (XRV) progenitors. In these cases, ERV–XRV interactions have been documented and include ( a) recombination to result in ERV–XRV chimeras, ( b) ERV induction of immune self-tolerance to XRV antigens, ( c) ERV antigen interference with XRV receptor binding, and ( d) interactions resulting in both enhancement and restriction of XRV infections. Whereas the mechanisms governing recombination and immune self-tolerance have been partially determined, enhancement and restriction of XRV infection are virus specific and only partially understood. This review summarizes interactions between six unique ERV–XRV pairs, highlighting important ERV biological functions and potential evolutionary histories in vertebrate hosts. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 9 is February 16, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Real-space observation of ferroelectrically induced magnetic spin crystal in SrRuO3

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. D. Seddon ◽  
D. E. Dogaru ◽  
S. J. R. Holt ◽  
D. Rusu ◽  
J. J. P. Peters ◽  
...  
Keyword(s):  
Hall Effect ◽  
Density Functional ◽  
Hysteresis Loops ◽  
Real Space ◽  
Zero Field ◽  
Force Microscopy ◽  
Switching Regime ◽  
Conflicting Evidence ◽  
Magnetic Spin

AbstractUnusual features in the Hall Resistivity of thin film systems are frequently associated with whirling spin textures such as Skyrmions. A host of recent investigations of Hall Hysteresis loops in SrRuO3 heterostructures have provided conflicting evidence for different causes for such features. We have constructed an SrRuO3-PbTiO3 (Ferromagnetic – Ferroelectric) bilayer that exhibits features in the Hall Hysteresis previously attributed to a Topological Hall Effect, and Skyrmions. Here we show field dependent Magnetic Force Microscopy measurements throughout the key fields where the ‘THE’ presents, revealing the emergence to two periodic, chiral spin textures. The zero-field cycloidal phase, which then transforms into a ‘double-q’ incommensurate spin crystal appears over the appearance of the ‘Topological-like’ Hall effect region, and develop into a ferromagnetic switching regime as the sample reaches saturation, and the ‘Topological-like’ response diminishes. Scanning Tunnelling Electron Microscopy and Density Functional Theory is used to observe and analyse surface inversion symmetry breaking and confirm the role of an interfacial Dzyaloshinskii–Moriya interaction at the heart of the system.

Advancing Socioeconomic Rights Through Interdisciplinary Factfinding: Opportunities and Challenges

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Sarah Knuckey ◽  
Joshua D. Fisher ◽  
Amanda M. Klasing ◽  
Tess Russo ◽  
Margaret L. Satterthwaite
Keyword(s):  
Human Rights ◽  
Mixed Methods ◽  
Social Science ◽  
Science Volume ◽  
Lessons Learned ◽  
Limited Resources ◽  
Annual Review ◽  
Publication Date ◽  
Socioeconomic Rights ◽  
Human Rights Movement

The human rights movement is increasingly using interdisciplinary, multidisciplinary, mixed-methods, and quantitative factfinding. There has been too little analysis of these shifts. This article examines some of the opportunities and challenges of these methods, focusing on the investigation of socioeconomic human rights. By potentially expanding the amount and types of evidence available, factfinding's accuracy and persuasiveness can be strengthened, bolstering rights claims. However, such methods can also present significant challenges and may pose risks in individual cases and to the human rights movement generally. Interdisciplinary methods can be costly in human, financial, and technical resources; are sometimes challenging to implement; may divert limited resources from other work; can reify inequalities; may produce “expertise” that disempowers rightsholders; and could raise investigation standards to an infeasible or counterproductive level. This article includes lessons learned and questions to guide researchers and human rights advocates considering mixed-methods human rights factfinding. Expected final online publication date for the Annual Review of Law and Social Science, Volume 17 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Conversation and Culture

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Simeon Floyd
Keyword(s):  
Conversation Analysis ◽  
Quantitative Methods ◽  
Sequential Analysis ◽  
Contemporary Literature ◽  
Annual Review ◽  
Publication Date ◽  
Face To Face ◽  
Qualitative And Quantitative Methods ◽  
Language Studies ◽  
Speech Communities

Conversation analysis is a method for the systematic study of interaction in terms of a sequential turn-taking system. Research in conversation analysis has traditionally focused on speakers of English, and it is still unclear to what extent the system observed in that research applies to conversation more generally around the world. However, as this method is now being applied to conversation in a broader range of languages, it is increasingly possible to address questions about the nature of interactional diversity across different speech communities. The approach of pragmatic typology first applies sequential analysis to conversation from different speech communities and then compares interactional patterns in ways analogous to how traditional linguistic typology compares morphosyntax. This article discusses contemporary literature in pragmatic typology, including single-language studies and multilanguage comparisons reflecting both qualitative and quantitative methods. This research finds that microanalysis of face-to-face interaction can identify both universal trends and culture-specific interactional tendencies. Expected final online publication date for the Annual Review of Anthropology, Volume 50 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Mechanical Patterning in Animal Morphogenesis

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Yonit Maroudas-Sacks ◽  
Kinneret Keren
Keyword(s):  
Pattern Formation ◽  
Large Scale ◽  
Coarse Grained ◽  
Annual Review ◽  
Publication Date ◽  
Biochemical Processes ◽  
Substantial Progress ◽  
Biological Pattern Formation ◽  
Effective Theories ◽  
Biochemical Signals

Morphogenesis is one of the most remarkable examples of biological pattern formation. Despite substantial progress in the field, we still do not understand the organizational principles responsible for the robust convergence of the morphogenesis process across scales to form viable organisms under variable conditions. Achieving large-scale coordination requires feedback between mechanical and biochemical processes, spanning all levels of organization and relating the emerging patterns with the mechanisms driving their formation. In this review, we highlight the role of mechanics in the patterning process, emphasizing the active and synergistic manner in which mechanical processes participate in developmental patterning rather than merely following a program set by biochemical signals. We discuss the value of applying a coarse-grained approach toward understanding this complex interplay, which considers the large-scale dynamics and feedback as well as complementing the reductionist approach focused on molecular detail. A central challenge in this approach is identifying relevant coarse-grained variables and developing effective theories that can serve as a basis for an integrated framework for understanding this remarkable pattern-formation process. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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