Nonlinear polarization evolution using time-dependent density functional theory

• Published in: The Journal of chemical physics Vol. 150; no. 9; pp. 094101 - 94111
• Main Authors: Uemoto, Mitsuharu, Kuwabara, Yuki, Sato, Shunsuke A., Yabana, Kazuhiro
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics 07.03.2019
• Subjects: Amplitudes; Density functional theory; Electric fields; Electron density; Evolution; Feature extraction; First principles; Physics; Plasma; Polarization; Power series; Time dependence
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/1.5068711

We propose a theoretical and computational approach to investigate temporal behavior of a nonlinear polarization in a perturbative regime induced by an intense and ultrashort pulsed electric field. First-principles time-dependent density functional theory is employed to describe the electron dynamics. Temporal evolution of third-order nonlinear polarization is extracted from a few calculations of electron dynamics induced by pulsed electric fields with the same time profile but different amplitudes. We discuss characteristic features of the nonlinear polarization evolution as well as an extraction of nonlinear susceptibilities and time delays by fitting the polarization. We also carry out a decomposition of temporal and spatial changes in the electron density in power series with respect to the field amplitude. It helps to get insight into the origin of the nonlinear polarization in atomic scale.