Berry curvature and shift vector effects at high-order wave mixing in biased bilayer graphene

Fuente: arXiv
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Main Authors: Avetissian, H. K., Matevosyan, H. H., Mkrtchian, G. F.
Format: Preprint
Published: 2024
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author Avetissian, H. K.
Matevosyan, H. H.
Mkrtchian, G. F.
author_facet Avetissian, H. K.
Matevosyan, H. H.
Mkrtchian, G. F.
contents In this work, we present a microscopic quantum theory that elucidates the nonlinear and nonperturbative optical response of biased bilayer graphene subjected to bichromatic strong laser fields. This response is analyzed using a four-band Hamiltonian derived from \textit{ab initio} calculations. For the laser-stimulated dynamics, we employ structure gauge-invariant evolutionary equations to accurately describe the evolution of the single-particle density matrix across the entire Brillouin zone. The resonant generation of electron-hole pairs by the high-frequency component of the field, combined with the induction of high-order harmonic generation and high-order wave mixing by the strong low-frequency field component, leads to significant alterations in the resulting spectra. These changes are driven by the effects of Berry curvature and the shift vector, which modify the relative contributions of interband and intraband channels, thereby fundamentally reshaping the radiation spectra at high-order frequency multiplication. The numerical results are further supported by approximate analytical calculations, demonstrating that high-order wave mixing can be modeled using the classical trajectory analysis of electron-hole pairs, with Berry curvature and the shift vector significantly influencing the saddle-point equations.
format Preprint
id arxiv_https___arxiv_org_abs_2409_06269
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Berry curvature and shift vector effects at high-order wave mixing in biased bilayer graphene
Avetissian, H. K.
Matevosyan, H. H.
Mkrtchian, G. F.
Mesoscale and Nanoscale Physics
In this work, we present a microscopic quantum theory that elucidates the nonlinear and nonperturbative optical response of biased bilayer graphene subjected to bichromatic strong laser fields. This response is analyzed using a four-band Hamiltonian derived from \textit{ab initio} calculations. For the laser-stimulated dynamics, we employ structure gauge-invariant evolutionary equations to accurately describe the evolution of the single-particle density matrix across the entire Brillouin zone. The resonant generation of electron-hole pairs by the high-frequency component of the field, combined with the induction of high-order harmonic generation and high-order wave mixing by the strong low-frequency field component, leads to significant alterations in the resulting spectra. These changes are driven by the effects of Berry curvature and the shift vector, which modify the relative contributions of interband and intraband channels, thereby fundamentally reshaping the radiation spectra at high-order frequency multiplication. The numerical results are further supported by approximate analytical calculations, demonstrating that high-order wave mixing can be modeled using the classical trajectory analysis of electron-hole pairs, with Berry curvature and the shift vector significantly influencing the saddle-point equations.
title Berry curvature and shift vector effects at high-order wave mixing in biased bilayer graphene
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2409.06269