Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Phys Rev Lett. 2013 Apr 26;110(17):176803. doi: 10.1103/PhysRevLett.110.176803. Epub 2013 Apr 23.
We report on low-temperature scanning tunneling spectroscopy investigations of the (sqrt[3]×sqrt[3]) Bi/Ag(111)R30° surface alloy which provides a giant Rashba-type spin splitting. We observed spectroscopic features that are assigned to two Rashba-split bands. Quantum interference mapping shows that backscattering is not only allowed below but also above the Rashba energy. We argue that the observed behavior can be understood within the Bloch picture where k refers to the crystal momentum and the velocity of an electronic state is defined as v(n)(E) = 1/ℏ ∇(k)E(n)(k). The analysis of the energy dispersion of scattering channels reveals a conventional Rashba splitting for the unoccupied Rashba bands, while hybridization is observed in the occupied states.
我们报告了（sqrt[3]×sqrt[3]）Bi/Ag（111）R30°表面合金的低温扫描隧道光谱研究，该合金提供了巨大的 Rashba 型自旋劈裂。我们观察到了光谱特征，这些特征被分配给两个 Rashba 分裂带。量子干涉映射表明，背散射不仅在 Rashba 能量以下而且在其以上都是允许的。我们认为，观察到的行为可以在 Bloch 图像中得到理解，其中 k 是指晶体动量，电子态的速度定义为 v(n)(E) = 1/ℏ∇(k)E(n)(k)。散射通道的能量色散分析揭示了未占据 Rashba 带的传统 Rashba 劈裂，而在占据态中观察到了杂化。
