Effects of relaxation on the photovoltaic effect and possibility for photocurrent within the transparent region

Abstract

In this work, the authors explore the possibility of photocurrents in metals that break both inversion and time-reversal symmetries within the transparent region, i.e., where neither Drude absorption nor interband transitions can occur. The authors show that the photocurrent is $O({\ensuremath{\omega}}_{J}/\ensuremath{\gamma})$ with the frequency of the induced current ${\ensuremath{\omega}}_{J}$ and the scattering rate $\ensuremath{\gamma}$ when ${\ensuremath{\omega}}_{J}$ $\ensuremath{\ll}$ $\ensuremath{\gamma}$. While dc photocurrent vanishes for finite $\ensuremath{\gamma}$, the theory here also indicates that nonvanishing photocurrent can appear even in the transparent region if $\ensuremath{\omega}$ $\ensuremath{\gg}$ $\ensuremath{\gamma}$.