Bulk photovoltaic effects in the presence of a static electric field

TL;DR

This paper investigates third-order dc photocurrents in biased insulators, revealing new jerk, injection, and shift current phenomena, with theoretical and physical insights, extending the understanding of bulk photovoltaic effects.

Contribution

It introduces and characterizes third-order photocurrents, including jerk, injection, and shift currents, expanding the theoretical framework of bulk photovoltaic effects.

Findings

Identification of three third-order photocurrents: jerk, injection, and shift.

Growth of photocurrents as powers of illumination time in ideal conditions.

Physical interpretation of these currents via semiclassical wave packet dynamics.

Abstract

This paper presents a study of dc photocurrents in biased insulators to the third order in the electric field. We find three photocurrents which are characterized by physical divergences of the third-order free-electron polarization susceptibility. In the absence of momentum relaxation and saturation effects, these dc photocurrents grow as $t^n$ $(n=2,1,0)$ with illumination time. The photocurrents are dubbed \textit{jerk}, third-order injection, and third-order shift current, respectively, and are generalizations of the second-order injection and shift currents of the bulk photovoltaic effect. We also revisit the theory of the bulk photovoltaic effect and include Fermi surface contributions which are important in metals. Finally, we show that injection, shift, and jerk currents admit simple physical interpretations in terms of semiclassical wave packet dynamics in electric fields. Experimental signatures and extensions to higher-order susceptibilities are also discussed.