Glide-Symmetric Z2 Magnetic Topological Crystalline Insulators PDF Download
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Author: Heejae Kim
Publisher: Springer Nature
ISBN: 9811690774
Category : Computers
Languages : en
Pages : 171
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Book Description
This book presents a comprehensive theory on glide-symmetric topological crystalline insulators. Beginning with developing a theory of topological phase transitions between a topological and trivial phase, it derives a formula for topological invariance in a glide-symmetric topological phase when inversion symmetry is added into a system. It also shows that the addition of inversion symmetry drastically simplifies the formula, providing insights into this topological phase, and proposes potential implementations. Lastly, based on the above results, the author establishes a way to design topological photonic crystals. Allowing readers to gain a comprehensive understanding of the glide-symmetric topological crystalline insulators, the book offers a way to produce such a topological phase in various physical systems, such as electronic and photonic systems, in the future.
Author: Heejae Kim
Publisher: Springer Nature
ISBN: 9811690774
Category : Computers
Languages : en
Pages : 171
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Book Description
This book presents a comprehensive theory on glide-symmetric topological crystalline insulators. Beginning with developing a theory of topological phase transitions between a topological and trivial phase, it derives a formula for topological invariance in a glide-symmetric topological phase when inversion symmetry is added into a system. It also shows that the addition of inversion symmetry drastically simplifies the formula, providing insights into this topological phase, and proposes potential implementations. Lastly, based on the above results, the author establishes a way to design topological photonic crystals. Allowing readers to gain a comprehensive understanding of the glide-symmetric topological crystalline insulators, the book offers a way to produce such a topological phase in various physical systems, such as electronic and photonic systems, in the future.
Author: C.L. Kane
Publisher: Elsevier Inc. Chapters
ISBN: 0128086823
Category : Science
Languages : en
Pages : 42
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Book Description
We give a pedagogical introduction to theory of topological insulators. Following an introduction to the role of topology in band theory, we discuss several examples in detail. These include theories of the electric polarization in one dimension, the integer quantum Hall effect in two dimensions and topological insulators in two and three dimensions. We close with a brief discussion of topological crystalline insulators, nodal semimetals, topological superconductivity and topological defects.
Author: An Zhao
Publisher: Open Dissertation Press
ISBN: 9781361341209
Category :
Languages : en
Pages :
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Book Description
This dissertation, "Theoretical Study of Magnetic Topological Insulators" by An, Zhao, 赵安, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: In recent years, the discovery of topological insulators brought a topological classification of materials and opened a new field in condensed matter physics. Due to the nontrivial topological properties, the topological insulators have insulating bulk and metallic edge/surface relating to some exotic physics such as quantum anomalous Hall effect, quantum spin Hall effect, and magneto-electric effect. Followed realizations of the Z2 topological insulators in two and three dimensions, the quantum anomalous Hall effect was realized in the magnetic-doped topological insulators very recently, which attracts intensive interest. In this thesis, the magnetic topological insulators as a consequence of time-reversal symmetry breaking in the Z2 topological insulators in two or three dimensions are studied. As an introduction, a review of the topological insulators including some relevant theories is given. The approaches involved in this study are also presented. The results can be summarized in two parts. First, the quantum anomalous Hall effect can be found on the two-dimensional decorated lattice with spin-orbit coupling and electron-electron interaction. Without interaction, this model exhibits the quantum spin Hall effect and has at bands in the middle of the spectra. A at-band ferrimagnetism which breaks the time-reversal symmetry and a charge-density wave can be induced by the electron-electron interaction. Altogether they can modulate the Chern number of the system and give rise to the quantum anomalous Hall effect. In the second part, the realization of the quantum anomalous Hall effect in magnetic-doped topological insulator thin films is investigated. With an effective Hamiltonian of the surface states of a topological insulator thin _lm, the condition of the quantum anomalous Hall effect and the behavior of the longitudinal and Hall conductivity is given, which agrees with the experimental results. The effects of the structural inversion asymmetry potential and the particle-hole symmetry breaking term are studied. With a thin _lm model of the three-dimensional topological insulator, it is shown that the lateral surface states account for the non-quantized value of the Hall conductance and the nonzero longitudinal conductance. The quantized Hall conductance restores when the lateral surface state electrons are thoroughly localized by disorder. The quantum anomalous Hall phase in magnetic topological insulator thin film in the present of disorder is also studied. The disorder will shrink the regime of the quantum anomalous Hall effect in a thick film and becomes an obstacle to the realization of the quantum anomalous Hall effect. DOI: 10.5353/th_b5194784 Subjects: Condensed matter
Author: Kenji Yasuda
Publisher: Springer Nature
ISBN: 981157183X
Category : Computers
Languages : en
Pages : 109
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Book Description
This book reveals unique transport phenomena and functionalities in topological insulators coupled with magnetism and superconductivity. Topological insulators are a recently discovered class of materials that possess a spin-momentum-locked surface state. Their exotic spin texture makes them an exciting platform for investigating emergent phenomena, especially when coupled with magnetism or superconductivity. Focusing on the strong correlation between electricity and magnetism in magnetic topological insulators, the author presents original findings on current-direction-dependent nonreciprocal resistance, current-induced magnetization reversal and chiral edge conduction at the domain wall. In addition, he demonstrates how the coupling between superconductivity and topological surface state leads to substantial nonreciprocal resistance. The author also elucidates the origins of these phenomena and deepens readers’ understanding of the topologically nontrivial electronic state. The book includes several works which are published in top journals and were selected for the President’s Award by the University of Tokyo and for the Ikushi Prize, awarded to distinguished Ph.D. students in Japan.
Author: Chaowei Hu
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Topological materials are materials whose electronic band structures are described by certain non-trivial topological invariants. Forty years ago the importance of band topology in condensed matter physics was first recognized when the quantum Hall effect (QHE) was found to be related with the integer Chern number in two-dimensional (2D) electron gas. Since 2008, the discovery of three-dimensional (3D) topological insulators (TI) with a non-trivial topological invariant and gapless surface state has taken the field into a new era. Various new topological phases were proposed and band topology has become a new way to classify the state of matter. The design, synthesis and characterization of new topological materials pave essential basis to uncovering novel physics arising from non-trivial band topology and its interplay with various degrees of freedom such as spin, orbital and charge. Today, with more sought-after novel topological phases, emergent phenomena such as surface Fermi arcs, chiral anomaly, quantum anomalous Hall effect were discovered and enable future technological advances including topological quantum computation. A new topological phase can be created when additional symmetry breaking is introduced into an existing topological phase. For example, by breaking the time reversal symmetry of a 3D TI through ferromagnetism (FM), one can get a Chern insulator in its 2D limit, where QHE can be realized without external magnetic field and gives topologically-protected dissipationless chiral edge states. This phenomenon, the so-called quantum anomalous Hall effect (QAHE), has been long sought since its early proposal in the yet-to-be-realized Haldane model for graphene lattice with opposite magnetic field at neighboring atoms in 1988. Therefore, the realization of QAHE in magnetically-doped TI Cr0.15(Bi0.1Sb0.9)1.85Te3 thin films in 2013 was revolutionary. However, the unavoidable sample inhomogeneity in doped materials restrains the investigation of associated emergent phenomena in mK-regime. Ideally, magnetism from intrinsic magnetic atoms in a crystal can provide more homogeneous electronic and magnetic properties than the magnetism from dopants. To realize QAHE at higher temperatures, the intrinsic magnetic TIs with only clean topological bands but no other bands at the Fermi level are strongly desired. In 2018, MnBi2Te4 was discovered to be the first of such kinds, as an antiferromagnetic (AFM) TI with intrinsic magnetic Mn site. It is a layered van der Waals (vdW) material. When the magnetism orders below 24 K, the spins are FM aligned in the ab plane but AFM coupled along the c axis. In 2D limit, MnBi2Te4 films can have a net magnetization either in odd-layer devices, or when the even-layer devices are in the spin-flop state above ~ 3.5 T and the forced FM state above ~ 8 T. These time-reversal-symmetry breaking states are ideal for realizing the Chern insulator state. Indeed, QAHE was experimentally observed at 0 T and 1.6 K in a 5-layer device and quantized Hall conductance was realized when the even-layer devices enter the forced FM state above the saturation field of 8 T. Following this line, for QAHE to be realized at zero field and higher temperature, it is strongly desirable if the FM alignment of Mn spins can be accessed at a lower or even zero field. To do so, one must weaken the interlayer AFM interactions between [MnBi2Te4] layers. We thus propose to introduce n-1 nonmagnetic TI [Bi2Te3] layers between [MnBi2Te4] layers to get natural heterostructures of MnBi2nTe3n+1. By this rational design, we can increase the distance between the neighboring [MnBi2Te4] layers and thus reduce the interlayer AFM interaction. Under such a design principle we successfully grew single crystals of MnBi4Te7 (n=2), MnBi6Te10 (n=3) and MnBi8Te13 (n=4). Then with the physical property characterization, first-principles calculations and angle-resolved photoemission spectroscopy measurements, for the first time, we demonstrated that MnBi4Te7 is an intrinsic AFM TI with saturation field 40 times smaller than that of MnBi2Te4, and that MnBi8Te13 is the first realization of an intrinsic FM axion insulator, proving the success of our material design principle. The manipulation of magnetism is crucial to access different magnetic topological phase and novel physics. In MnBi2nTe3n+1, the control of the magnetism from AFM to FM by n is only discrete. To achieve a fine and continuous control of the magnetic transition, we doped Sb to MnBi4Te7 where the interlayer AFM coupling is weak and more tunable. Through single crystal growth, transport, thermodynamic, neutron diffraction measurements, we show that under Sb doping, MnBi4Te7 evolves from AFM to FM and then ferrimagnetic. We attribute this to the formation of Mn_(Bi, Sb) antisites upon doping, which results in additional Mn sublattices that modify the delicate interlayer magnetic interactions and changes the overall magnetism. We further investigate the effect of antisites on the band topology using the first-principles calculations. Without considering antisites, the series evolves from AFM topological insulator (x = 0) to FM axion insulators. In the exaggerated case of 16.7\% of periodic antisites, the band topology is modified and type-I magnetic Weyl semimetal phase can be realized at intermediate doping. Therefore, this doping series provides a fruitful platform with rich and continuously tunable magnetism and topology. After we achieve FM in MnBi2nTe3n+1, for practical applications especially in the pursuit of high temperature QAHE when fluctuations become important, the study on magnetic dynamics is indispensable too. We investigated the magnetic dynamics in FM MnBi8Te13 and Sb doped MnBi4Te7 and MnBi6Te10 using AC susceptibility and magneto-optical imaging. Slow relaxation behavior is observed in all three compounds, suggesting its universality among FM MnBi2nTe3n+1. The origin of the relaxation behavior is attributed to the irreversible domain movements since they only appear below the saturation fields when FM domains form and evolve. These FM domains are very soft, as revealed by the low-field fine-structured domains and high-field sea-urchin-shaped remnant-state domains imaged via the magneto-optical measurements. Finally, we attribute the rare "double-peak" behavior observed in the AC susceptibility under small DC bias fields to the very soft FM domain formations. This study provides a thorough understanding of the soft FM in highly anisotropic magnets. As the first intrinsic antiferromagnetic topological insulator, MnBi2Te4 is still the major material platform to search for QAHE, so its material optimization is very urged. We develop the chemical-vapor-transport (CVT) growth for of MnBi2Te4, which has a higher success rate in observation of the field-induced quantized Hall conductance in 6-layer devices. Through comparative studies between our CVT-grown and flux-grown MnBi2Te4, we find that CVT-grown MnBi2Te4 is marked with higher Mn occupancy on the Mn site, slightly higher Mn_Bi antisites and smaller carrier concentration. On the device end, thin film from CVT-grown sample shows by far the highest mobility of 2500 cm2 V s in MnBi2Te4 devices with the quantized Hall conductance appearing at 1.8 K and 8 T. This study provides a route to obtain high-quality single crystals of MnBi2Te4 that are promising to make superior devices and realize emergent phenomena. In summary, we have discovered and established MnBi4Te7 and MnBi8Te13 as new intrinsic magnetic topological insulators. In particular, we provide deep understanding of the importance of material design, synthesis and chemical doping to the magnetism and topology in the series. The growths of high-quality single crystals and the study of magnetic dynamics provide essential basis for the search of QAHE in MnBi2nTe3n+1. Our works will shed light on future endeavors in finding novel magnetic topological materials as well as searching for QAHE and the associated emergent phenomena in the condensed matter field
Author: Manijeh Razeghi
Publisher: Springer Science & Business Media
ISBN: 0387287515
Category : Technology & Engineering
Languages : en
Pages : 894
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Book Description
Provides a multidisciplinary introduction to quantum mechanics, solid state physics, advanced devices, and fabrication Covers wide range of topics in the same style and in the same notation Most up to date developments in semiconductor physics and nano-engineering Mathematical derivations are carried through in detail with emphasis on clarity Timely application areas such as biophotonics , bioelectronics
Author: David Vanderbilt
Publisher: Cambridge University Press
ISBN: 110715765X
Category : Science
Languages : en
Pages : 395
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Book Description
An introduction to the role of Berry phases in our modern understanding of the physics of electrons in solids.
Author: Andrew Zangwill
Publisher: Cambridge University Press
ISBN: 1316583260
Category : Science
Languages : en
Pages : 470
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Book Description
Physics at Surfaces is a unique graduate-level introduction to the physics and chemical physics of solid surfaces, and atoms and molecules that interact with solid surfaces. A subject of keen scientific inquiry since the last century, surface physics emerged as an independent discipline only in the late 1960s as a result of the development of ultra-high vacuum technology and high speed digital computers. With these tools, reliable experimental measurements and theoretical calculations could at last be compared. Progress in the last decade has been truly striking. This volume provides a synthesis of the entire field of surface physics from the perspective of a modern condensed matter physicist with a healthy interest in chemical physics. The exposition intertwines experiment and theory whenever possible, although there is little detailed discussion of technique. This much-needed text will be invaluable to graduate students and researchers in condensed matter physics, physical chemistry and materials science working in, or taking graduate courses in, surface science.
Author: Daniel Arovas
Publisher:
ISBN: 9781505583311
Category :
Languages : en
Pages : 186
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Book Description
Lecture Notes on Condensed Matter Physics (A Work in Progress)By Daniel Arovas
Author: Aloke Paul
Publisher: Springer
ISBN: 331907461X
Category : Science
Languages : en
Pages : 543
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Book Description
In this book basic and some more advanced thermodynamics and phase as well as stability diagrams relevant for diffusion studies are introduced. Following, Fick’s laws of diffusion, atomic mechanisms, interdiffusion, intrinsic diffusion, tracer diffusion and the Kirkendall effect are discussed. Short circuit diffusion is explained in detail with an emphasis on grain boundary diffusion. Recent advances in the area of interdiffusion will be introduced. Interdiffusion in multi-component systems is also explained. Many practical examples will be given, such that researches working in this area can learn the practical evaluation of various diffusion parameters from experimental results. Large number of illustrations and experimental results are used to explain the subject. This book will be appealing for students, academicians, engineers and researchers in academic institutions, industry research and development laboratories.
