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arXiv · 2602.22463

Many-Body effects beyond excitons in second-harmonic generation of monolayer MoS$_{2}$

Peio Garcia-Goiricelaya·Julen Ibañez-Azpiroz
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Abstract

We present a quantitative study of many-body effects including the three-particle level on second-harmonic generation in monolayer MoS$_2$. Our approach combines many-body perturbation theory with time-dependent current-density-functional theory within an \textit{ab initio} framework in the optical limit. The inclusion of two-particle excitonic effects \textit{via} a dynamical long-range linear exchange-correlation kernel reproduces the qualitative features of the second-harmonic response, but underestimates the experimentally reported magnitude by nearly a factor of two. By incorporating three-particle trionic correlations through a static long-range quadratic exchange-correlation kernel, we achieve significantly improved quantitative agreement with experiment. These findings highlight the role of many-body interactions beyond the excitonic level in accurately describing second-order optical responses in two-dimensional semiconductors.

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Peio Garcia-Goiricelaya, Julen Ibañez-Azpiroz. 2026-02-25. Many-Body effects beyond excitons in second-harmonic generation of monolayer MoS$_{2}$. https://arxiv.org/abs/2602.22463

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