Frequency-resolved microscopic current density analysis of linear and nonlinear optical phenomena in solids

TL;DR

This paper introduces a frequency-resolved microscopic current density analysis method to study electron dynamics in solids, providing detailed insights into linear and nonlinear optical phenomena at the microscopic level.

Contribution

The paper develops a novel frequency-resolved microscopic current density analysis technique based on first-principles simulations to analyze electron dynamics in solids.

Findings

Captured the nature of delocalized electrons in metals.

Characterized bound electrons in semiconductors and insulators.

Provided microscopic insights into optical responses.

Abstract

We perform a frequency-resolved analysis of electron dynamics in solids to obtain microscopic insight into linear and nonlinear optical phenomena. For the analysis, we first compute the electron dynamics under optical electric fields and evaluate the microscopic current density as a function of time and space. Subsequently, we perform the Fourier transformation on the microscopic current density and obtain the corresponding quantity in the frequency domain. The frequency-resolved microscopic current density provides insight into the microscopic electron dynamics in real-space at the frequency of linear and nonlinear optical responses. We apply frequency-resolved microscopic current density analysis to light-induced electron dynamics in aluminum, silicon, and diamond based on the first-principles electron dynamics simulation according to the time-dependent density functional theory. Consequently, the nature of delocalized electrons in metals and bound electrons in semiconductors and insulators is suitably captured by the developed scheme.