光电流
光电导性
材料科学
光电子学
能量收集
电流(流体)
弹道传导
放松(心理学)
工作(物理)
物理
功率(物理)
电子
心理学
社会心理学
量子力学
热力学
作者
Alonso J Campos-Hernandez,Yang Zhang,Adolfo G. Grushin,Fernando de Juan
摘要
The generation of shift and ballistic photocurrents in non-centrosymmetric materials represents a promising alternative mechanism for light energy harvesting. Many studies have focused on finding the best suited materials by maximizing the photocurrent magnitude, but estimating the actual efficiency requires knowledge of the light-induced dc photoconductivity and is rarely considered. Using the recently proposed jerk current as photoconductivity, in this work we show that only ballistic photocurrents have finite efficiency in the limit of large relaxation times τ. Moreover, at zero temperature the only ballistic current which is finite for unpolarized light is the magnetic injection current, only present in magnetic materials. We present a band structure expression for the efficiency of such photocurrent, showing that it scales as (ħΩ – Eg)2 near the band edge, and we present its frequency dependence for a simple tight-binding model. Our work provides a new tool to guide the search for efficient energy harvesting based on the magnetic injection current.
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