Photogalvanic effect in monolayer black phosphorus
Photogalvanic effect in monolayer black phosphorus
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DOI：
10.1088/0957-4484/26/45/455202
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发表时间：
2015-10
期刊：
影响因子：
3.5
通讯作者：
Yiqun Xie;Lei Zhang;Y. Zhu;Lei Liu;Hong Guo
中科院分区：
文献类型：
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作者：
Yiqun Xie;Lei Zhang;Y. Zhu;Lei Liu;Hong Guo
我们报告的第一性原理的理论方法分析线性和圆形的光电流效应（PGE）的基础上的非平衡绿色函数形式主义的密度泛函理论。利用这种方法，我们研究了在单层黑磷（MBP）中掺杂硫原子的PGE现象。杂质掺杂打破了原始MBP的空间反转对称性，导致具有垂直于MBP晶格之字形方向的镜面反射平面的Cs对称性。受这种对称性的支配，在Z字形和扶手椅方向上都诱导出线性PGE，并且沿沿着Z字形方向诱导出圆形PGE。一个强大的宽带光响应被发现从近红外到可见光范围的MBP设备。PGE具有很强的各向异性：锯齿方向的光响应比扶手椅方向的光响应大一个数量级。我们确定所观察到的PGE的起源为从杂质和价带到导带的带间跃迁，其涉及从光子到电子的角动量的转移。
We report a first-principles theoretical approach for analyzing linear and circular photogalvanic effects (PGEs) based on density functional theory within the nonequilibrium Green’s function formalism. Using this approach we investigate the PGE phenomena in monolayer black phosphorus (MBP) doped with sulfur atoms. The impurity doping breaks the space inversion symmetry of pristine MBP, leading to a Cs symmetry with a mirror reflection plane normal to the zigzag direction of the MBP lattice. Governed by this symmetry, a linear PGE is induced in both zigzag and armchair directions, and a circular PGE is induced along the zigzag direction. A robust broadband photoresponse is found from the near-infrared to the visible range for the MBP device. There is a strong anisotropy in PGE: photoresponse in the zigzag direction can be larger by an order of magnitude than that in the armchair direction. We identify the origin of the observed PGE as the inter-band transitions from the impurity and valence bands to the conduction bands, which involves a transfer of angular momentum from photons to electrons.