Substantial optical dielectric enhancement by volume compression in LiAsSe${}_2$

Abstract

Based on first-principles calculations, we predict a substantial increase in the optical dielectric function of LiAsSe${}_2$ under pressure. We find that the optical dielectric constant is enhanced threefold under volume compression. This enhancement is mainly due to the dimerization strength reduction of the one-dimensional (1D) As--Se chains in LiAsSe${}_2$, which significantly alters the wavefunction phase mismatch between two neighboring chains and changes the transition intensity. By developing a tight-binding model of the interacting 1D chains, the essential features of the low-energy electronic structure of LiAsSe${}_2$ are captured. Our findings are important for understanding the fundamental physics of LiAsSe${}_2$ and provide a feasible way to enhance the material optical response that can be applied to light harvesting for energy applications.

13 pages, 6 figures

References in corpus (3)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• First-Principles Calculation of the Bulk Photovoltaic Effect in the Polar Compounds LiAsS${}_{\text{2}}$, LiAsSe${}_{\text{2}}$, and NaAsSe${}_{\text{2}}$
• Tunable electronic anisotropy in single-crystal A2Cr3As3 (A = K, Rb) quasi-one-dimensional superconductors