Calculation of spin states of photoelectrons emitted from spin-polarized surface states of Bi(111) surfaces with a mirror symmetry
Calculation of spin states of photoelectrons emitted from spin-polarized surface states of Bi(111) surfaces with a mirror symmetry
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镜面对称Bi(111)表面自旋极化表面态发射的光电子自旋态的计算
DOI：
10.1103/physrevb.95.205436
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发表时间：
2017
影响因子：
3.7
通讯作者：
F. Komori
中科院分区：
文献类型：
--
作者：
Katsuyoshi Kobayashi;K. Yaji;K. Kuroda;F. Komori
从理论上研究了Bi(111)表面自旋极化表面态激发的光电子的自旋态。重点讨论了具有镜像对称性的电子态。我们提出了一种利用平面波基密度泛函方法的结果计算光电子自旋期望值的方法。我们表明，末态的自由电子近似不足以解释在自旋和角分辨光电子能谱中获得的实验结果。我们指出了光电子发射中时间反转对称性的两个效应。一种是自旋取向的离面分量与时间反转态的离面分量相反。这一性质可用于通过用破坏镜面对称性的偏振来发射光来区分样品的取向。另一种是由于光电发射过程中固有的时间反转对称性的破坏，导致初始态和时间反转状态之间的光致发射强度的不对称性。
Spin states of photoelectrons excited from spin-polarized surface states of Bi(111) surfaces are theoretically studied. The electronic states with a mirror symmetry are focused on in particular. We present a method for calculating spin expectation values of photoelectrons using results of density-functional methods in the plane-wave basis. We show that the free-electron approximation for final states is not sufficient for explaining an experimental result obtained in spin- and angle-resolved photoelectron spectroscopy. We point out two effects of the time-reversal symmetry in photoelectron emission. One is that the out-of-plane component of spin orientation is reversed to that of the time-reversed state. This property may be used for distinguishing the orientation of samples by shedding light with polarizations that break the mirror symmetry. Another is the asymmetry in photoemission intensity between an initial state and its time-reversed state due to the breaking of the time-reversal symmetry intrinsic in the photoemission process.