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arXiv · 2105.08874

Giant Optomechanical Coupling in the Charge Density Wave State of Tantalum Disulfide

Anubhab Haldar·Cristian L. Cortes·Stephen K. Gray·Sahar Sharifzadeh·Pierre Darancet
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Abstract

We study the coupling of light and the structural order parameter in the charge density wave (CDW) state of the layered transition-metal dichalcogenide, Tantalum Disulfide ($1T-\mathrm{TaS_2}$). Using time-dependent density functional theory calculations of the dielectric properties along the distortions coordinates, we show that $1T-\mathrm{TaS_2}$ displays very large change in its dielectric function along the amplitude (Higgs) mode due to the coupling of the periodic lattice distortion with an in-plane metal-insulator transition, leading to optomechanical coupling coefficients two orders of magnitude larger than the ones of diamond and ErFeO$_3$. In addition, we derive an effective model of the light-induced dynamics, which is in quantitative agreement with experimental observations in $1T-\mathrm{TaS_2}$. We show that light-induced dynamics of the structural order parameter in $1T-\mathrm{TaS_2}$ can be deterministically controlled to engineer large third-order non-linear optical susceptibilities. Our findings suggest that CDW materials are promising active materials for non-linear optics.

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Anubhab Haldar, Cristian L. Cortes, Stephen K. Gray, Sahar Sharifzadeh, Pierre Darancet. 2021-05-31. Giant Optomechanical Coupling in the Charge Density Wave State of Tantalum Disulfide. https://arxiv.org/abs/2105.08874

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