Topological Phase Control of Surface States in Bi2Se3 via Spin-Orbit Coupling Modulation through Interface Engineering between HfO2- X

Kwangsik Jeong, Hanbum Park, Jimin Chae, Kyung Ik Sim, Won Jun Yang, Jong Hoon Kim, Seok Bo Hong, Jae Hoon Kim, Mann Ho Cho

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The direct control of topological surface states in topological insulators is an important prerequisite for the application of these materials. Conventional attempts to utilize magnetic doping, mechanical tuning, structural engineering, external bias, and external magnetic fields suffer from a lack of reversible switching and have limited tunability. We demonstrate the direct control of topological phases in a bismuth selenide (Bi2Se3) topological insulator in 3 nm molecular beam epitaxy-grown films through the hybridization of the topological surface states with the hafnium (Hf) d-orbitals in the topmost layer of an underlying oxygen-deficient hafnium oxide (HfO2) substrate. The higher angular momentum of the d-orbitals of Hf is hybridized strongly by topological insulators, thereby enhancing the spin-orbit coupling and perturbing the topological surface states asymmetry in Bi2Se3. As the oxygen defect is cured or generated reversibly by external electric fields, our research facilitates the complete electrical control of the topological phases of topological insulators by controlling the defect density in the adjacent transition metal oxide. In addition, this mechanism can be applied in other related topological materials such as Weyl and Dirac semimetals in future endeavors to facilitate practical applications in unit-element devices for quantum computing and quantum communication.

Original languageEnglish
Pages (from-to)12215-12226
Number of pages12
JournalACS Applied Materials and Interfaces
Issue number10
Publication statusPublished - 2020 Mar 11

Bibliographical note

Funding Information:
This study was supported by the Joint Program for Samsung Electronics–Yonsei University by the Samsung Research Funding Center for Future Technology (SRFC-MA1502-01). This work was supported in part by the Yonsei University Research Fund (Yonsei Frontier Laboratory Young Researcher Supporting Program) of 2018.

Publisher Copyright:
Copyright © 2020 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)


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