光电流
各向异性
物理
GSM演进的增强数据速率
可视化
流量(数学)
凝聚态物理
天体物理学
理论物理学
统计物理学
量子力学
半金属
机械
带隙
数据挖掘
人工智能
计算机科学
作者
Yu-Xuan Wang,Xin-Yue Zhang,Chunhua Li,Xiaohan Yao,Ruihuan Duan,Thomas K. M. Graham,Zheng Liu,Fazel Tafti,David Broido,Ying Ran,Brian B. Zhou
出处
期刊:Nature Physics
[Springer Nature]
日期:2023-01-23
卷期号:19 (4): 507-514
被引量:5
标识
DOI:10.1038/s41567-022-01898-0
摘要
Materials that rectify light into current in their bulk are desired for optoelectronic applications. In Weyl semimetals that break inversion symmetry, bulk photocurrents may arise due to nonlinear optical processes that are enhanced near the Weyl nodes. However, the photoresponse of these materials is commonly studied by scanning photocurrent microscopy, which convolves the effects of photocurrent generation and collection. Here we directly image the photocurrent flow inside the type-II Weyl semimetals WTe2 and TaIrTe4 using high-sensitivity quantum magnetometry with nitrogen-vacancy centre spins. We elucidate a mechanism for bulk photocurrent generation, which we call the anisotropic photothermoelectric effect, where unequal thermopowers along different crystal axes drive intricate circulations of photocurrent around the photoexcitation. Using overlapping scanning photocurrent microscopy and magnetic imaging at the interior and edges of the sample, we visualize how the anisotropic photothermoelectric effect stimulates the long-range photocurrent collected in our WTe2 and TaIrTe4 devices through the Shockley–Ramo mechanism. Our results highlight a widely relevant source of current flow and will inspire photodetectors that utilize bulk materials with thermoelectric anisotropy. Understanding the fundamental mechanisms of photocurrent generation is important for photodetector design. Now, the anisotropy of the thermal properties of Weyl semimetals is shown to generate circulating photocurrents.
科研通智能强力驱动
Strongly Powered by AbleSci AI