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Three-dimensional topological insulators have protected Dirac-cone surface states. In this paper we propose magnetic field induced topological insulator thin film ordered states in which coherence is established spontaneously between top…

Strongly Correlated Electrons · Physics 2013-05-29 Dagim Tilahun , Byounghak Lee , E. M. Hankiewicz , A. H. MacDonald

Topological insulators represent a novel state of matter with surface charge carriers having a massless Dirac dispersion and locked helical spin polarization. Many exciting experiments have been proposed by theory, yet, their execution have…

Materials Science · Physics 2014-10-27 Katharina Höfer , Christoph Becker , Diana Rata , Jesse Swanson , Peter Thalmeier , Liu Hao Tjeng

Recently, the quantum spin-Hall edge channels of two-dimensional colloidal nanocrystals of the topological insulator Bi$_2$Se$_3$ were observed directly. Motivated by this development, we reconsider the four-band effective model which has…

Mesoscale and Nanoscale Physics · Physics 2024-03-29 Lucas Maisel Licerán , Sebastiaan Koerhuis , Daniel Vanmaekelbergh , Henk Stoof

Ultrathin films of Na3Bi on insulating substrates are desired for opening a bulk band gap and generating the quantum spin Hall effect from a topological Dirac semimetal, though continuous films in the few nanometer regime have been…

Breaking time-reversal symmetry in three-dimensional topological insulator thin films can lead to different topological quantum phases, such as the Chern insulator (CI) phase, and the axion insulator (AI) phase. Using first-principles…

Strongly Correlated Electrons · Physics 2021-05-18 N. Pournaghavi , M. F. Islam , Rajibul Islam , Carmine Autieri , Tomasz Dietl , C. M. Canali

Topological insulators (TIs) are a class of materials characterized by an insulting bulk and high mobility topologically protected surface states, making them promising candidates for future optoelectronic and quantum devices. Although…

Topological insulators are a new class of materials, that exhibit robust gapless surface states protected by time-reversal symmetry. The interplay between such symmetry-protected topological surface states and symmetry-broken states (e.g.…

Highly crystalline and easily feasible topological insulator-superconductor (TI-SC) heterostructures are crucial for the development of practical topological qubit devices. The optimal superconducting layer for TI-SC heterostructures should…

Mesoscale and Nanoscale Physics · Physics 2024-07-08 Renjie Xie , Min Ge , Shaozhu Xiao , Jiahui Zhang , Jiachang Bi , Xiaoyu Yuan , Hee Taek Yi , Baomin Wang , Seongshik Oh , Yanwei Cao , Xiong Yao

Topologically protected gapless edge/surface states are phases of quantum matter which behave as massless Dirac fermions, immunizing against disorders and continuous perturbations. Recently, a new class of topological insulators (TIs) with…

Materials Science · Physics 2020-09-30 Baizhan Xia , Shengjie Zheng , Liang Tong , Junrui Jiao , Guiju Duan , Dejie Yu

In an ideal 3D topological insulator (TI), the bulk is insulating and the surface conducting due to the existence of metallic states that are localized on the surface; these are the topological surface states. Quaternary Bi-based compounds…

Bi$_2$Se$_3$ is a widely studied 3D topological insulator having potential applications in optics, electronics, and spintronics. When the thickness of these films decrease to less than approximately 6 nm, the top and bottom surface states…

Materials Science · Physics 2024-06-19 Saadia Nasir , Walter J. Smith , Thomas E. Beechem , Stephanie Law

Topological insulators (TIs) are intriguing materials for advanced computing applications based on spintronics because they can host robust spin effects. For instance, TIs have intrinsically large spin generation enabled by their large…

Mesoscale and Nanoscale Physics · Physics 2025-03-11 Sharadh Jois , Gregory M. Stephen , Nick Blumenschein , Patrick J. Taylor , Aubrey T. Hanbicki , Adam L. Friedman

We study spin conductivity of the surface states in a thin film of a topological insulator with Kubo formulas. Hybridization between the different sides of the film opens a gap at the Dirac point. We found that in the gapped region spin…

Mesoscale and Nanoscale Physics · Physics 2021-01-01 R. S. Akzyanov

We report the observation of second harmonic generation with high conversion efficiency $\sim 0.005\%$ in the terahertz regime from thin films of the topological insulator Bi$_2$Se$_3$ that exhibit the linear photogalvanic effect, measured…

Strongly Correlated Electrons · Physics 2024-06-11 Jonathan Stensberg , Xingyue Han , Zhuoliang Ni , Xiong Yao , Xiaoyu Yuan , Debarghya Mallick , Akshat Gandhi , Seongshik Oh , Liang Wu

Bi2Se3 is theoretically predicted1 2and experimentally observed2,3 to be a three dimensional topological insulator. For possible applications, it is important to understand the electronic structure of the planar device. In this work,…

Recently, it was shown that quantum spin Hall insulator (QSHI) phase with a gap wide enough for practical applications can be realized in the ultra thin films constructed from two inversely stacked structural elements of trivial band…

Materials Science · Physics 2017-11-01 S. V. Eremeev , I. A. Nechaev , E. V. Chulkov

Uniform and large area synthesis of bulk insulating ultrathin films is an important subject toward applications of a surface of three dimensional topological insulators (3D-TIs) in various electronic devices. Here we report epitaxial growth…

Mesoscale and Nanoscale Physics · Physics 2017-04-17 Ngoc Han Tu , Yoichi Tanabe , Yosuke Satake , Khuong Kim Huynh , Le Huu Phuoc , Stephane Yu Matsushita , Katsumi Tanigaki

Bulk Bi2Te3 is known to be a topological insulator. We investigate surface states of Bi2Te3(111) thin films using density-functional theory including spin-orbit coupling. We construct a method to unambiguously identify surface states of…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 Kyungwha Park , J. J. Heremans , V. W. Scarola , Djordje Minic

We study electronic states and topological invariants of (001)-films of topological crystalline insulator (TCI) Pb_{x}Sn_{1-x}Te. Gapless surface Dirac cones on bulk TCIs become gapped in thin films due to finite-size effect, which is…

Mesoscale and Nanoscale Physics · Physics 2014-09-29 Hideyuki Ozawa , Ai Yamakage , Masatoshi Sato , Yukio Tanaka

Material defects remain as the main bottleneck to the progress of topological insulators (TIs). In particular, efforts to achieve thin TI samples with dominant surface transport have always led to increased defects and degraded mobilities,…