title: Tuning the Fermi level with topological phase transition by internal strain in a topological insulator Bi2Se3 thin film.
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.
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Tae-Hyeon
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: KwangSik
authors.initials: K
authors.lastname: Jeong
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Byung Cheol
authors.initials: BC
authors.lastname: Park
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Hyejin
authors.initials: H
authors.lastname: Choi
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Sang Han
authors.initials: SH
authors.lastname: Park
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Republic of Korea.
authors.forename: Seonghoon
authors.initials: S
authors.lastname: Jung
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Republic of Korea.
authors.forename: Jaehun
authors.initials: J
authors.lastname: Park
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Kwang-Ho
authors.initials: KH
authors.lastname: Jeong
authors.affiliation: Division of Industrial Metrology, Korea Research Institute of Standards and Science, Republic of Korea.
authors.forename: Jeong Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Republic of Korea. mh.cho@yonsei.ac.kr.
authors.forename: Mann-Ho
authors.initials: MH
authors.lastname: Cho