Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8581, Japan.
Phys Rev Lett. 2010 Apr 16;104(15):156805. doi: 10.1103/PhysRevLett.104.156805. Epub 2010 Apr 15.
The electronic structure of ultrathin Ag(111) films covered with a square root(3) x square root(3)-Bi/Ag ordered alloy was investigated by means of spin- and angle-resolved photoemission spectroscopy. Surface-state (SS) bands, spin split by the Rashba interaction, selectively couple to the quantum-well state (QWS) bands, originally spin degenerate, in the metal film. Gaps are found to open between QWS and SS with parallel spins, while free-electron-like QWS dispersions are observed for antiparallel spin configurations. The present results demonstrate that in a nonmagnetic metal film the spin degeneracy of the valence levels can be lifted by hybridization with Rashba-type SS bands.
采用自旋和角分辨光电子能谱研究了覆盖有平方根(3)×平方根(3)-Bi/Ag 有序合金的超薄 Ag(111)薄膜的电子结构。表面态 (SS) 带由 Rashba 相互作用分裂，选择性地与金属膜中原先自旋简并的量子阱态 (QWS) 带耦合。发现平行自旋的 QWS 和 SS 之间出现能隙，而对于反平行自旋构型，则观察到自由电子样 QWS 色散。本研究结果表明，在非磁性金属薄膜中，价层的自旋简并性可以通过与 Rashba 型 SS 带的杂化来消除。
