Reversal of the Circular Dichroism in Angle-Resolved Photoemission from Bi2Te3
Reversal of the Circular Dichroism in Angle-Resolved Photoemission from Bi2Te3
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DOI：
10.1103/physrevlett.110.216801
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发表时间：
2013-05-22
影响因子：
8.6
通讯作者：
Rader, O.
中科院分区：
文献类型：
--
作者：
Scholz, M. R.;Sanchez-Barriga, J.;Rader, O.
拓扑绝缘体表面的螺旋狄拉克费米子显示出很强的圆二色性，这被解释为是由于初始状态的自旋角动量，初始状态的轨道角动量，或实验装置的手性。所有这些解释都与我们从Bi2Te3获得的数据相冲突，Bi2Te3依赖于光子能量并显示出几个符号变化。我们的一步光电发射计算耦合从头算理论确认的符号变化，并分配的二色性的最终状态效果。相反，用线偏振光激发的光电子的自旋极化仍然是初始状态下自旋的可靠探针。
The helical Dirac fermions at the surface of topological insulators show a strong circular dichroism which has been explained as being due to either the initial-state spin angular momentum, the initial-state orbital angular momentum, or the handedness of the experimental setup. All of these interpretations conflict with our data from Bi2Te3 which depend on the photon energy and show several sign changes. Our one-step photoemission calculations coupled to ab initio theory confirm the sign change and assign the dichroism to a final-state effect. Instead, the spin polarization of the photoelectrons excited with linearly polarized light remains a reliable probe for the spin in the initial state.