Tuning of Topological Dirac States via Modification of van der Waals Gap in Strained Ultrathin Bi2Se3 Films

Won Jun Yang, Chang Woo Lee, Da Sol Kim, Hyun Sik Kim, Jong Hyeon Kim, Hwan Young Choi, Young Jai Choi, Jae Hoon Kim, Kyungwha Park, Mann Ho Cho

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Robust massless Dirac states with helical spin textures were realized at the boundaries of topological insulators such as van der Waals (vdW) layered Bi2Se3 family compounds. Topological properties of massless Dirac states can be controlled by varying the film thickness, external stimuli, or environmental factors. Here, we report single-crystal-quality growth of ultrathin Bi2Se3 films on flexible polyimide sheets and manipulation of the Dirac states by varying the vdW gap. X-ray diffraction unambiguously demonstrates that under uniaxial bending stress the vdW gap substantially changes with interatomic-layer distances unaltered. Terahertz and photoelectron spectroscopy indicate tuning of the number of quantum conducting channels and of work function, by the stress, respectively. Surprisingly, under compressive strain, transport measurements reveal dimensional crossover and suppressed weak antilocalization. First-principles calculations support the observation. Our findings suggest that variation of vdW gap is an effective means of tuning the Fermi level and topological Dirac states for spintronics and quantum computation.

Original languageEnglish
Pages (from-to)23739-23748
Number of pages10
JournalJournal of Physical Chemistry C
Volume122
Issue number41
DOIs
Publication statusPublished - 2018 Oct 18

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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