Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 6: TR: Nanoelectronics II: Spintronics and Magnetotransport

TT 6.8: Vortrag

Montag, 22. März 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.