Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor
Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor
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DOI：
10.1103/physrevb.97.161104
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发表时间：
2018-03
影响因子：
3.7
通讯作者：
Y. Kinoshita;N. Kida;T. Miyamoto;M. Kanou;T. Sasagawa;H. Okamoto
中科院分区：
文献类型：
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作者：
Y. Kinoshita;N. Kida;T. Miyamoto;M. Kanou;T. Sasagawa;H. Okamoto
固体中由相对论自旋-轨道相互作用引起的自旋分裂能带为在亚皮秒尺度上操纵自旋极化电子提供了新的机会。在这里，我们报告了一个这样的例子，在块状Rashba型极性半导体BiTeBr.用圆偏振的飞秒激光脉冲共振激发Rashba型自旋分裂能带之间的带间跃迁，发射出强太赫兹电磁波。通过切换圆偏振，发射的太赫兹波的相位被反转。这表明观测到的太赫兹辐射来源于由Dirac态的非对称布居产生的亚皮秒自旋偏振光电流。我们的结果为电流感生太赫兹辐射及其位相控制提供了一种新的途径。
The spin-splitting energy bands induced by the relativistic spin-orbit interaction in solids provide a new opportunity to manipulate the spin-polarized electrons on the sub-picosecond time scale. Here, we report one such example in a bulk Rashba-type polar semiconductor BiTeBr. Strong terahertz electromagnetic waves are emitted after the resonant excitation of the interband transition between the Rashba-type spin-splitting energy bands with a femtosecond laser pulse circularly polarized. The phase of the emitted terahertz waves is reversed by switching the circular polarization. This suggests that the observed terahertz radiation originates from the subpicosecond spin-polarized photocurrents, which are generated by the asymmetric depopulation of the Dirac state. Our result provides a new way for the current-induced terahertz radiation and its phase control by the circular polarization of incident light without external electric fields.