Spin mapping of surface and bulk Rashba states in ferroelectric α-GeTe(111) films
Spin mapping of surface and bulk Rashba states in ferroelectric α-GeTe(111) films
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DOI：
10.1103/physrevb.94.201403
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发表时间：
2016-11-09
影响因子：
3.7
通讯作者：
Schoenhense, G.
中科院分区：
文献类型：
--
作者：
Elmers, H. J.;Wallauer, R.;Schoenhense, G.
铁电半导体中体反转对称性的破缺导致电子体能带的Rashba型自旋分裂。这是由铁电α-GeTe（111）薄膜中的电子带的自旋极化的综合映射所示，使用配备有成像自旋滤波器的飞行时间动量显微镜，能够同时测量超过10 000个数据点。实验揭示了相反的自旋螺旋度的内部和外部Rashba带与不同的自旋极化与理论预测一致，确认了复杂的自旋纹理散装Rashba状态。外带的自旋极化率大约是内带的两倍，这证明了自旋轨道效应与带态的轨道组成有关。GeTe的可切换内电场意味着自旋电子器件的新功能。
The breaking of bulk inversion symmetry in ferroelectric semiconductors causes a Rashba-type spin splitting of electronic bulk bands. This is shown by a comprehensive mapping of the spin polarization of the electronic bands in ferroelectric alpha-GeTe(111) films using a time-of-flight momentum microscope equipped with an imaging spin filter that enables a simultaneous measurement of more than 10 000 data points. The experiment reveals an opposite spin helicity of the inner and outer Rashba bands with a different spin polarization in agreement with theoretical predictions, confirming a complex spin texture of bulk Rashba states. The outer band has about twice larger spin polarization than the inner one, giving evidence of a spin-orbit effect being related to the orbital composition of the band states. The switchable inner electric field of GeTe implies new functionalities for spintronic devices.