Spatially dispersive circular photogalvanic effect in a Weyl semimetal
Spatially dispersive circular photogalvanic effect in a Weyl semimetal
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DOI：
10.1038/s41563-019-0421-5
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发表时间：
2019-09-01
期刊：
影响因子：
41.2
通讯作者：
Agarwal, Ritesh
中科院分区：
文献类型：
--
作者：
Ji, Zhurun;Liu, Gerui;Agarwal, Ritesh
Weyl半金属（WSMs）是具有破缺反转和/或时间反转对称性的物质的无间隙拓扑态。当圆偏振光以正入射照射时，wsm可以支持循环光电流。在这里，我们报道了一个空间色散圆形光电效应（s-CPGE）在WSM中发生的空间变化光束轮廓。我们的分析表明，s-CPGE是由对称选择规则与不对称载流子激励和弛豫动力学相结合控制的。通过对WSM最小模型的s-CPGE进行评估，获得了光电流的频率相关缩放行为。从可见光到中红外波段的波长相关测量显示了s-CPGE响应中的Berry曲率奇点和波段反转的证据。我们提出s-CPGE作为一种很有前途的拓扑带性质光谱探针，具有通过在拓扑材料上形成光场来存储、操纵和传输信息来控制光响应的潜力。
Weyl semimetals (WSMs) are gapless topological states of matter with broken inversion and/or time reversal symmetry. WSMs can support a circulating photocurrent when illuminated by circularly polarized light at normal incidence. Here, we report a spatially dispersive circular photogalvanic effect (s-CPGE) in a WSM that occurs with a spatially varying beam profile. Our analysis shows that the s-CPGE is controlled by a symmetry selection rule combined with asymmetric carrier excitation and relaxation dynamics. By evaluating the s-CPGE for a minimal model of a WSM, a frequency-dependent scaling behaviour of the photocurrent is obtained. Wavelength-dependent measurements from the visible to mid-infrared range show evidence of Berry curvature singularities and band inversion in the s-CPGE response. We present the s-CPGE as a promising spectroscopic probe for topological band properties, with the potential for controlling photoresponse by patterning optical fields on topological materials to store, manipulate and transmit information.