1203.6718 (Guangfen Wu et al.)

Precise tuning of the vertical location of helical surface states in
topological insulator heterostructures via dual-proximity effect    [PDF]

Guangfen Wu, Hua Chen, Yan Sun, Xiaoguang Li, Ping Cui, Cesare Franchini, Jinlan Wang, Xing-Qiu Chen, Zhenyu Zhang

In integrating topological insulators (TI) with conventional materials for potential device applications, one crucial issue is how the topological surface states (TSS) will behave in such heterostructures. We use first-principles approaches to establish precise tunability of the vertical location of the TSS via novel dual-proximity effects. By depositing a conventional insulator (CI) (ZnM, M = S, Se, and Te) overlayer onto a TI substrate (Bi2Se3 or Bi2Te3), we found that, the TSS can float to the top of the ZnM film, or stay put at the CI/TI interface, or be pushed down deeper into the TI substrate. These contrasting behaviors imply a rich variety of possible quantum phase transitions in the hybrid systems, dictated by three key material-specific properties of the CI: the strength of spin-orbit coupling, band gap, and work function. These discoveries lay the foundation for precise manipulation of the real space properties of TSS in TI heterostructures of diverse technological significance.

View original: http://arxiv.org/abs/1203.6718