Tuning the Fermi level with topological phase transition by internal strain in a topological insulator Bi2Se3 thin film

Tae Hyeon Kim, Kwangsik Jeong, Byung Cheol Park, Hyejin Choi, Sang Han Park, Seonghoon Jung, Jaehun Park, Kwang Ho Jeong, Jeong Won Kim, Jae Hoon Kim, Mann Ho Cho

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

In a three-dimensional topological insulator Bi2Se3, a stress control for band gap manipulation was predicted but no systematic investigation has been performed yet due to the requirement of large external stress. We report herein on the strain-dependent results for Bi2Se3 films of various thicknesses that are grown via a self-organized ordering process. Using small angle X-ray scattering and Raman spectroscopy, the changes of d-spacings in the crystal structure and phonon vibration shifts resulted from stress are clearly observed when the film thickness is below ten quintuple layers. From the UV photoemission/inverse photoemission spectroscopy (UPS/IPES) results and ab initio calculations, significant changes of the Fermi level and band gap were observed. The deformed band structure also exhibits a Van Hove singularity at specific energies in the UV absorption experiment and ab initio calculations. Our results, including the synthesis of a strained ultrathin topological insulator, suggest a new direction for electronic and spintronic applications for the future.

Original languageEnglish
Pages (from-to)741-751
Number of pages11
JournalNanoscale
Volume8
Issue number2
DOIs
Publication statusPublished - 2016 Jan 14

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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