Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 6: TR: Nanoelectronics II: Spintronics and Magnetotransport
TT 6.8: Talk
Monday, March 22, 2010, 15:45–16:00, H19
Oscillatory crossover from two dimensional to three dimensional topological insulators — •Chao-Xing Liu1, HaiJun Zhang2, Binghai Yan3, Xiao-Liang Qi4, Thomas Frauenheim3, Xi Dai2, Zhong Fang2, and Shou-Cheng Zhang4 — 1EP3 and Institute for Theoretical Physics and Astrophysics, University of Wurzburg, 97074 Wurzburg, Germany — 2IOP, Chinese Academy of Sciences, Beijing 100190, China — 3Bremen Center for Computational Materials Science, Universitat Bremen, 28359 Bremen, Germany — 4Department of Physics, Stanford University, Stanford, CA 94305-4045
Topological insulators (TIs) are new states of quantum matter with the surface states protected by time-reversal symmetry, which can exist both in two-dimensional (2D) system and three-dimensional (3D) system. In this work, we would like to investigate the crossover regime from 3D TIs to 2D TIs when the sample thickness is reduced. Based on the four band effective model, we find that the crossover occurs in an oscillatory fashion as a function of the film thickness, alternating between topologically trivial and non-trivial 2D behavior. A physical picture is provided to understand the origin of the oscillation. Furthermore ab initio calculation is performed to study the realistic Bi2Se3 and Bi2Te3 thin film and confirm the analytical results. These results not only establisch the relation between the TIs with the different dimensions, but also provide a new path to search for new TIs.