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Interfaces between exfoliated topological insulator Bi2Se3 and several transition metals deposited by sputtering were studied by XPS, SIMS, UPS and contact I-V measurements. Chemically clean interfaces can be achieved when coating Bi2Se3…

Mesoscale and Nanoscale Physics · Physics 2015-11-12 Weiguang Ye , A. B. Pakhomov , Shuigang Xu , Huanhuan Lu , Zefei Wu , Yu Han , Tianyi Han , Yingying Wu , Gen Long , Jiangxiazi Lin , Gu Xu , Yuan Cai , Lu-Tao Weng , Ning Wang

Bi2Se3 is a prototypical topological insulator which has a small band gap (~0.3 eV) and topologically protected conducting surface states. This material exhibits quite strong thermoelectric effects. Here we show in a mechanically exfoliated…

Angle-resolved photoelectron spectroscopy is used for a detailed study of the electronic structure of the topological insulator Bi2Se3. Nominally stoichiometric and calcium-doped samples were investigated. The pristine surface shows the…

We performed broadband optical transmission measurements of Bi2Se3 and In-doped Bi(1-x)In(x)2Se3 thin films, where in the latter the spin-orbit coupling (SOC) strength can be tuned by introducing In. Drude and interband transitions exhibit…

Materials Science · Physics 2019-11-11 Jiwon Jeon , Kwangnam Yu , Jiho Kim , Jisoo Moon , Seongshik Oh , E. J. Choi

Topological insulators are bulk semiconductors that manifest in-gap massless Dirac surface states due to the topological bulk-boundary correspondence principle [1-3]. These surface states have been a subject of tremendous ongoing interest,…

We investigate the bulk band structures and the surface states of Bi2Se3 and Bi2Te3 topological insulators using first-principles many-body perturbation theory based on the GW approximation. The quasiparticle self-energy corrections…

Mesoscale and Nanoscale Physics · Physics 2012-04-20 Oleg V. Yazyev , Emmanouil Kioupakis , Joel E. Moore , Steven G. Louie

Optical band gap properties of high-quality few-layer topological insulator Bi2Se3 thin films grown with magnetron sputtering are investigated using broadband absorption spectroscopy. We provide direct optical evidence of a rigid blue-shift…

Materials Science · Physics 2017-05-24 Yub Raj Sapkota , Asma Alkabsh , Aaron Walber , Hassana Samassekou , Dipanjan Mazumdar

Topological insulators represent a new state of quantum matter attractive to both fundamental physics and technological applications such as spintronics and quantum information processing. In a topological insulator, the bulk energy gap is…

In this work, we studied the bulk band structure of a topological insulator (TI) Bi2Se3 and determined the contributions of the Bi and Se orbital states to the valence bands using standing wave-excited hard x-ray photoemission spectroscopy…

We have performed angle-resolved photoemission spectroscopy on (PbSe)5(Bi2Se3)3m, which forms a natural multilayer heterostructure consisting of a topological insulator (TI) and an ordinary insulator. For m = 2, we observed a gapped…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 K. Nakayama , K. Eto , Y. Tanaka , T. Sato , S. Souma , T. Takahashi , Kouji Segawa , Yoichi Ando

We present our angle resolved photoelectron spectroscopy (ARPES) and density functional theory results on quaternary topological insulator (TI) BiSbTe1.25Se1.75 (BSTS) confirming the non-trivial topology of the surface state bands (SSBs) in…

Materials Science · Physics 2023-10-31 H. Lohani , P. Mishra , A. Banerjee , K. Majhi , R. Ganesan , U. Manju , D. Topwal , P. S. Anil Kumar , B. R. Sekhar

We report on microscopic tight-binding modeling of surface states in Bi$_2$Se$_3$ three-dimensional topological insulator, based on a sp$^3$ Slater-Koster Hamiltonian, with parameters calculated from density functional theory. The effect of…

Mesoscale and Nanoscale Physics · Physics 2014-11-04 A. Pertsova , C. M. Canali

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,…

Shubnikov-de-Haas oscillations were studied under high magnetic field in Bi$_2$Se$_3$ nanostructures grown by Chemical Vapor Transport, for different bulk carrier densities ranging from $3\times10^{19}\text{cm}^{-3}$ to…

Proximity-effect-induced superconductivity was studied in epitaxial topological insulator Bi2Se3 thin films grown on superconducting NbSe2 single crystals. A point contact spectroscopy (PCS) method was used at low temperatures down to 40…

We investigate the band dispersion and the spin texture of topologically protected surface states in the bulk topological insulators Bi2Se3 and Bi2Te3 by first-principles methods. Strong spin-orbit entanglement in these materials reduces…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 Oleg V. Yazyev , Joel E. Moore , Steven G. Louie

In this Letter we present scanning tunneling microscopy density-of-states measurements and electronic structure calculations of the topological insulator Bi2Se3. The measurements show significant background states in addition to the…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Megan Romanowich , Mal-Soon Lee , Duck-Young Chung , Jung-Hwan Song , S. D. Mahanti , Mercouri G. Kanatzidis , Stuart H. Tessmer

We report high-resolution spin-resolved photoemission spectroscopy (Spin-ARPES) measurements on the parent compound Sb of the recently discovered 3D topological insulator Bi1-xSbx [D. Hsieh et al., Nature 452, 970 (2008)]. By modulating the…

Mesoscale and Nanoscale Physics · Physics 2010-01-12 D. Hsieh , L. A. Wray , D. Qian , Y. Xia , Y. S. Hor , R. J. Cava , M. Z. Hasan

We discuss the ultrafast evolution of the surface electronic structure of the topological insulator Bi$_2$Te$_3$ following a femtosecond laser excitation. Using time and angle resolved photoelectron spectroscopy, we provide a direct…

We have investigated the optical properties of thin films of topological insulators Bi$_{2}$Te$_{3}$, Bi$_{2}$Se$_{3}$ and their alloys Bi$_2$(Te$_{1-x}$Se$_x$)$_3$ on BaF$_{2}$ substrates by a combination of infrared ellipsometry and…

Materials Science · Physics 2018-02-05 A. Dubroka , O. Caha , M. Hronček , P. Friš , M. Orlita , V. Holý , H. Steiner , G. Bauer , G. Springholz , J. Humlíček
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