Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan.
Phys Rev Lett. 2009 Oct 9;103(15):156801. doi: 10.1103/PhysRevLett.103.156801. Epub 2009 Oct 5.
A peculiar Rashba effect is found at a point in the Brillouin zone, where the time-reversal symmetry is broken, though this symmetry was believed to be a necessary condition for Rashba splitting. This finding obtained experimentally by photoemission measurements on a Bi/Si(111)-(sqrt(3) x sqrt(3)) surface is fully confirmed by a first-principles theoretical calculation. We found that the peculiar Rashba effect is simply understood by the two-dimensional symmetry of the surface, and that this effect leads to an unconventional nonvortical Rashba spin structure at a point with time-reversal invariance.
在布里渊区的一个点上发现了一种特殊的 Rashba 效应，尽管时间反转对称性被认为是 Rashba 劈裂的必要条件，但在这个点上，时间反转对称性被打破了。通过对 Bi/Si(111)-(sqrt(3) x sqrt(3))表面进行光电子能谱测量，实验上得到了这一发现，这一发现被第一性原理理论计算完全证实。我们发现，通过表面的二维对称性，可以简单地理解这种特殊的 Rashba 效应，而且这种效应导致了在时间反转不变的点上具有非常规非涡旋 Rashba 自旋结构。
