title: Robust gapless surface state and Rashba-splitting bands upon surface deposition of magnetic Cr on Bi2Se3.
abstract: The interaction between magnetic impurities and the gapless surface state is of critical importance for realizing novel quantum phenomena and new functionalities in topological insulators. By combining angle-resolved photoemission spectroscopic experiments with density functional theory calculations, we show that surface deposition of Cr atoms on Bi2Se3 does not lead to gap opening of the surface state at the Dirac point, indicating the absence of long-range out-of-plane ferromagnetism down to our measurement temperature of 15 K. This is in sharp contrast to bulk Cr doping, and the origin is attributed to different Cr occupation sites. These results highlight the importance of nanoscale configuration of doped magnetic impurities in determining the electronic and magnetic properties of topological insulators.
authors.affiliation: State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University , Beijing 100084, P.R. China.
authors.forename: Eryin
authors.initials: E
authors.lastname: Wang
authors.forename: Peizhe
authors.initials: P
authors.lastname: Tang
authors.forename: Guoliang
authors.initials: G
authors.lastname: Wan
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Fedorov
authors.forename: Ireneusz
authors.initials: I
authors.lastname: Miotkowski
authors.forename: Yong P
authors.initials: YP
authors.lastname: Chen
authors.forename: Wenhui
authors.initials: W
authors.lastname: Duan
authors.forename: Shuyun
authors.initials: S
authors.lastname: Zhou
keywords: angle-resolved photoemission spectroscopy (ARPES); ferromagnetism; time-reversal symmetry; topological insulator