Identification of magnetic dopants on the surfaces of topological insulators: Experiment and theory for Fe on Bi 2 Te 3 (111)

作者：Damien West, Yi‐Yang Sun, Shengbai Zhang, Tao Zhang, Xu-Cun Ma, P. Cheng, Yunfei Zhang, X. Chen, Jili Jia, Qi‐Kun Xue · 发表于：Physical Review B · 年份：2012 · DOI：10.1103/physrevb.85.081305 · 被引用次数：55 · 研究领域：Topological Materials and Phenomena、Quantum many-body systems、Advanced Condensed Matter Physics

Magnetic impurities are crucial for probing spin-polarized topological surface states. Scanning tunneling microscopy (STM) studies of Fe on the Bi${}_{2}$Te${}_{3}$(111) surface are preformed and unveil distinct impurity structures of unknown origin which exhibit temperature-dependent characteristics. Using density functional theory with spin-orbit coupling, we show that Fe prefers highly coordinated subsurface configurations. By comparing simulated STM images we can explain the experimental results of both low-temperature deposition, in which Fe exists in metastable states of which only the transition-metal Bi split interstitial is STM visible, and after room-temperature annealing, in which iron forms substitutional Fe${}_{\mathrm{Bi}}$.