Interface-enhanced helicity dependent photocurrent in metal/semimetal bilayers
Interface-enhanced helicity dependent photocurrent in metal/semimetal bilayers
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DOI：
10.1103/physrevb.103.174437
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
H. Hirose;M. Kawaguchi;Y. Lau;Z. Chi;F. Freimuth;K. Takanashi;M. Hayashi
中科院分区：
文献类型：
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作者：
H. Hirose;M. Kawaguchi;Y. Lau;Z. Chi;F. Freimuth;K. Takanashi;M. Hayashi
固体中光-自旋相互作用的标志之一是依赖于光螺旋度的光电流的出现。近年来的研究表明，半金属薄膜的光生自旋电流和逆自旋霍尔效应导致了螺旋度相关的光电流（HDP）。我们研究了HDP在金属/半金属双层膜。与Bi单层膜相比，我们发现金属/Bi双层膜的HDP增强。对于双层膜，背照下的HDP的符号与前照下的相反。在所研究的双层膜中，Ag/Bi双层膜的背照光电流最大。利用扩散自旋输运模型，我们表明背照下的HDP符号反转是由自旋吸收和自旋电荷转换在界面上。当Bi层厚度较小时，这种界面效应有助于双层膜在正面照明下的HDP增强。这些结果表明，HDP可以用来评估具有强自旋轨道耦合的界面态。
One of the hallmarks of light-spin interaction in solids is the appearance of photocurrent that depends on the light helicity. Recent studies have shown that helicity dependent photocurrent (HDP) emerges due to light induced spin current and the inverse spin Hall effect of semimetal thin films. We have studied HDP in metal/semimetal bilayers. Compared to Bi single layer films, we find the HDP is enhanced in metal/Bi bilayers. For the bilayers, the sign of HDP under back illumination reverses from that of front illumination. The back illumination photocurrent is the largest for Ag/Bi bilayers among the bilayers studied. Using a diffusive spin transport model, we show that the HDP sign reversal under back illumination is caused by spin absorption and spin to charge conversion at the interface. Such interfacial effects contribute to the HDP enhancement under front illumination for the bilayers when the Bi layer thickness is small. These results show that the HDP can be used to assess interface states with strong spin orbit coupling.