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Indentation fracture toughness of single-crystal Bi2Te3 topological insulators

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Nano Research 2016年第4期9卷 1032-1042页

作者： Caterina Lamuta Anna Cupolillo Antonio Politano Ziya S. Aliev Mahammad B. Babanly Evgueni V. Chulkov Leonardo Pagnotta Department of Mechanical Energy and Management Engineering University ofCalabria Ponte P Bucci Cuba 44C 87036 Rende Italy Department of Physics University of Calabria Ponte P Bucci Cuba 31 C 87036 Rende Italy Institute of Catalysis and Inorganic Chemistry ANAS AZ1143 Baku Azerbaijian Institute of Physics ANAS AZ1143 Baku Azerbaijian Donostia International Physics Center (DIPC) Paseo de Manuel Lardizabal 4 20018 San Sebastian/Donostia Spain Departamento de Fisica de Materiales Universidad del Pals Vasco Apartado 1072 20080 San Sebastidn/Donostia Spain Centro de Fisica de Materiales CFM-Materials Physics Center MPC Centro Mixto CSIC-UPV/EHU Paseo de Manuel Lardizabal 5 20018 San Sebastion/Donostia Spain Saint Petersburg State University 198504 Saint Petersburg Russian Federation Tomsk State University 634050 Tomsk Russian Federation

Bismuth teUuride （Bi2Te3） is one of the most important commercial thermoelectric materials. In recent years, the discovery of topologically protected surface states in Bi chalcogenides has paved the way for their application in nanoelectronics. Determination of the fracture toughness plays a crucial role for the potential application of topological insulators in flexible electronics and nanoelectro- mechanical devices. Using depth-sensing nanoindentation tests, we investigated for the first time the fracture toughness of bulk single crystals of Bi2Te3 topological insulators, grown using the Bridgmantockbarger method. Our results highlight one of the possible pitfalls of the technology based on topological insulators.

关键词： topological insulators bismuth telluride (Bi2Te3) fracture toughness nanoindentation

A brief review on one-dimensional topological insulators and superconductors

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Science China(Physics,Mechanics & Astronomy) 2016年第3期59卷 39-47页

作者： Huai-Ming Guo Department of Physics Beihang University

Recently one-dimensional topological phases are gaining increasing attentions. Like two- and three-dimensional ones, Onedimensional systems are important in a complete understanding of the topological properties. One-dimensional topological phases have been realized using current experimental setups. Specially the signatures of Majorana fermions have been observed in onedimensional topological superconductors engineered with Rashiba nanowires. From the many studies, the paper reviews typical theoretical models of one-dimensional topological insulators and superconductors. For one-dimensional topological insulators, we introduce the Su-Schrieffer-Heeger, superlattices and Creutz models, while for topological superconductors the Kitaev model and Rashiba nanowire are introduced. These models not only provide an overview of one-dimensional topological phases, but also are the starting points for further studies.

关键词： one dimension topological insulators topological superconductors

On Mathematical Aspects of the Theory of topological insulators

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Acta Mathematica Sinica,English Series 2024年第1期40卷 81-106页

作者： Innocenti MARESIN Armen SERGEEV Egor TEPLYAKOV Department of Complex Analysis Steklov Mathematical Institute119991Gubkina 8MoscowRussia Moscow Institute of Physics and Technology 141701Institute per.9DolgoprudnyMoscow RegionRussia

This review is devoted to one of the most interesting and actively developing fields in condensed matter physics—theory of topological *** from its importance for theoretical physics,this theory enjoys numerous connections with modern mathematics,in particular,with topology and homotopy theory,Clifford algebras,K-theory and non-commutative *** the physical point of view topological invariance is equivalent to adiabatic *** insulators are characterized by the broad energy gap,stable under small deformations,which motivates application of topological methods.A key role in the study of topological ob jects in the solid state physics is played by their symmetry *** are three main types of symmetries—time reversion symmetry,preservation of the number of particles(charge symmetry)and PH-symmetry(particle-hole symmetry).Based on the study of symmetry groups and representation theory of Clifford algebras Kitaev proposed a classification of topological ob jects in solid state *** this review we pay special attention to the topological insulators invariant under time reversion.

关键词： topological insulators Bloch theory fermionic Fock spaces Kramers degeneration Maiorana states

A simple and efficient criterion for ready screening of potential topological insulators

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Science Bulletin 2017年第24期62卷 1649-1653页

作者： Guohua Cao Huijun Liu Xing-Qiu Chen Yan Sun Jinghua Liang Rui Yu Zhenyu Zhang Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology Wuhan University Wuhan 430072 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China International Center for Quantum Design of Functional Materials (ICQD) Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China

topological materials are a new and rapidly expanding class of quantum matter. To date, identification of the topological nature of a given compound material demands specific determination of the appropriate topological invariant through detailed electronic structure calculations. Here we present an efficient criterion that allows ready screening of potential topological materials, using topological insulators as prototypical examples. The criterion is inherently tied to the band inversion induced by spin-orbit coupling,and is uniquely defined by a minimal number of two elemental physical properties of the constituent elements: the atomic number and Pauling electronegativity. The validity and predictive power of the criterion is demonstrated by rationalizing many known topological insulators and potential candidates in the tetradymite and half-Heusler families, and the underlying design principle is naturally also extendable to predictive discoveries of other classes of topological materials.

关键词： topological insulators Band inversion Spin-orbit coupling Predictive design

Fractional topological insulators—A Bosonization Approach

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Journal of Modern Physics 2016年第1期7卷 118-128页

作者： D. Schmeltzer Physics Department City College of the City University of New York New York NY USA

A metallic disk with strong spin orbit interaction is investigated. The finite disk geometry introduces a confining potential. Due to the strong spin-orbit interaction and confining potential the metal disk is described by an effective one-dimensional model with a harmonic potential. The harmonic potential gives rise to classical turning points. As a result, open boundary conditions must be used. We bosonize the model and obtain chiral Bosons for each spin on the edge of the disk. When the filling fraction is reduced to the electron-electron interactions are studied by using the Jordan Wigner phase for composite fermions which give rise to a Luttinger liquid. When the metallic disk is in the proximity with a superconductor, a Fractional topological Insulator is obtained. An experimental realization is proposed. We show that by tunning the chemical potential we control the classical turning points for which a Fractional topological Insulator is realized.

关键词： Spin-Orbit Chiral Bosons Chains Metallic Disk topological insulators

Non-Hermitian topological Anderson insulators

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Science China(Physics,Mechanics & Astronomy) 2020年第6期63卷 2-12页

作者： Dan-Wei Zhang Ling-Zhi Tang Li-Jun Lang Hui Yan Shi-Liang Zhu Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials GPETR Center for Quantum Precision Measurement and SPTESouth China Normal UniversityGuangzhou 510006China National Laboratory of Solid State Microstructures School of PhysicsNanjing UniversityNanjing 210093China

Non-Hermitian systems can exhibit exotic topological and localization *** we elucidate the non-Hermitian effects on disordered topological systems using a nonreciprocal disordered Su-Schrieffer-Heeger *** show that the non-Hermiticity can enhance the topological phase against disorders by increasing bulk ***,we uncover a topological phase which emerges under both moderate non-Hermiticity and disorders,and is characterized by localized insulating bulk states with a disorder-averaged winding number and zero-energy edge *** topological phases induced by the combination of non-Hermiticity and disorders are dubbed non-Hermitian topological Anderson *** reveal that the system has unique non-monotonous localization behavior and the topological transition is accompanied by an Anderson *** properties are general in other non-Hermitian models.

关键词： topological insulators non-Hermitian systems localization properties

Machine-learning-driven on-demand design of phononic beams

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Science China(Physics,Mechanics & Astronomy) 2022年第1期65卷 33-44页

作者： Liangshu He Hongwei Guo Yabin Jin Xiaoying Zhuang Timon Rabczuk Yan Li School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China Institute of Photonics Department of Mathematics and PhysicsLeibniz UniversityHannover 30167Germany Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Institute of Structural Mechanics Bauhaus-Universitat WeimarWeimar D-99423Germany

The development of phononic crystals, especially their interaction with topological insulators, allows exploration of the anomalous properties of acoustic/elastic waves for various applications. However, rapidly and inversely exploring the geometry of specific targets remains a major challenge. In this work, we show how machine learning can address this challenge by studying phononic crystal beams using two different inverse design schemes. We first develop the theory of phononic beams using the transfer matrix method. Then, we use the reinforcement learning algorithm to effectively and inversely design the structural parameters to maximize the bandgap width. Furthermore, we employ the tandem-architecture neural network to solve the training-difficulty problem caused by inconsistent data and complete the task of inverse structure design with the targeted topological properties. The two inverse-design schemes have different adaptabilities, and both are characterized by high efficiency and stability. This work provides deep insights into the combination of machine learning, topological property,and phononic crystals and offers a reliable platform for rapidly and inversely designing complex material and structure properties.

关键词： phononic crystals elastic metamaterials topological insulators machine learning reinforcement learning

topological insulator nanostructures and devices

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Chinese Physics B 2013年第9期22卷 40-53页

作者：修发贤赵彤彤 State Key Laboratory of Surface Physics and Department of Physics Fudan University

topological insulators＇ properties and their potential device applications are reviewed. We also explain why topologi- cal insulator （TI） nanostructnres are an important avenue for research and discuss some methods by which TI nanostructures are produced and characterized. The rapid development of high-quality TI nanostructures provides an ideal platform to ex- ploit salient physical phenomena that have been theoretically predicted but not yet experimentally realized.

关键词： topological insulators nanostructures quantum spin Hall effect Aharonov-Bohm effect

A realistic topological p-n junction at the Bi2Se3 （0001） surface based on planar twin boundary defects

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Nano Research 2017年第5期10卷 1784-1793页

作者： Hugo Aramberri M. Carmen Munoz Jorge I. Cerda Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) Cantoblanco Madrid 28049 Spain

We propose a realistic topological p-n junction （TPNJ） by matching two Bi2Se3 （0001） slabs with opposite arrangements of planar twin boundary defects. The atomistic modeling of such a device leads to dislocation defects in the hexagonal lattice in several quintuple layers. Nevertheless, total energy calculations reveal that the interface relaxes, yielding a smooth geometrical transition that preserves the nearest-neighbors fcc-type geometry throughout these defect layers. The electronic, magnetic, and transport properties of the junction have then been calculated at the ab initio level under open boundary conditions, i.e., employing a thin-film geometry that is infinite along the electron transport direction. Indeed, a p-n junction is obtained with a built-in potential as large as 350 meV. The calculations further reveal the spin texture across the interface with unprecedented detail. As the main result, we obtain non-negligible transmission probabilities around the F point, which involve an electron spin-flip process while crossing the interface.

关键词： topological insulators p-n junctions spintronics electronic devices twin boundaries