Competing weak localization and weak antilocalization in ultrathin topological insulators

Murong Lang, Liang He, Xufeng Kou, Pramey Upadhyaya, Yabin Fan, Hao Chu, Ying Jiang, Jens H. Bardarson, Wanjun Jiang, Eun Sang Choi, Yong Wang, Nai Chang Yeh, Joel Moore, Kang L. Wang

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)


We demonstrate evidence of a surface gap opening in topological insulator (TI) thin films of (Bi0.57Sb0.43)2Te 3 below six quintuple layers through transport and scanning tunneling spectroscopy measurements. By effective tuning the Fermi level via gate-voltage control, we unveil a striking competition between weak localization and weak antilocalization at low magnetic fields in nonmagnetic ultrathin films, possibly owing to the change of the net Berry phase. Furthermore, when the Fermi level is swept into the surface gap of ultrathin samples, the overall unitary behaviors are revealed at higher magnetic fields, which are in contrast to the pure WAL signals obtained in thicker films. Our findings show an exotic phenomenon characterizing the gapped TI surface states and point to the future realization of quantum spin Hall effect and dissipationless TI-based applications.

Original languageEnglish
Pages (from-to)48-53
Number of pages6
JournalNano letters
Issue number1
Publication statusPublished - 2013 Jan 9

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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