Separation of top and bottom surface conduction in Bi2Te 3 thin films

Xinxin Yu, Liang He, Murong Lang, Wanjun Jiang, Faxian Xiu, Zhiming Liao, Yong Wang, Xufeng Kou, Peng Zhang, Jianshi Tang, Guan Huang, Jin Zou, Kang L. Wang

Research output: Contribution to journalArticlepeer-review

Abstract

Quantum spin Hall (QSH) systems are insulating in the bulk with gapless edges or surfaces that are topologically protected and immune to nonmagnetic impurities or geometric perturbations. Although the QSH effect has been realized in the HgTe/CdTe system, it has not been accomplished in normal 3D topological insulators. In this work, we demonstrate a separation of two surface conductions (top/bottom) in epitaxially grown Bi2Te3 thin films through gate dependent Shubnikov-de Haas (SdH) oscillations. By sweeping the gate voltage, only the Fermi level of the top surface is tuned while that of the bottom surface remains unchanged due to strong electric field screening effects arising from the high dielectric constant of Bi2Te3. In addition, the bulk conduction can be modulated from n- to p-type with a varying gate bias. Our results on the surface control hence pave a way for the realization of QSH effect in topological insulators which requires a selective control of spin transports on the top/bottom surfaces.

Original languageEnglish
Article number015705
JournalNanotechnology
Volume24
Issue number1
DOIs
Publication statusPublished - 2013 Jan 11

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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