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arXiv · 2105.12269

Impurity Screening and Friedel Oscillations in Floquet-driven Two-dimensional Metals

Mahmoud M. Asmar·Wang-Kong Tse
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Abstract

We develop a theory for the non-equilibrium screening of a charged impurity in a two-dimensional electron system under a strong time-periodic drive. Our analysis of the time-averaged polarization function and dielectric function reveals that Floquet driving modifies the screened impurity potential in two main regimes. In the weak drive regime, the time-averaged screened potential exhibits unconventional Friedel oscillations with multiple spatial periods contributed by a principal period modulated by higher-order periods, which are due to the emergence of additional Kohn anomalies in the polarization function. In the strong drive regime, the time-averaged impurity potential becomes almost unscreened and does not exhibit Friedel oscillations. This tunable Friedel oscillations is a result of the dynamic gating effect of the time-dependent driving field on the two-dimensional electron system.

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Mahmoud M. Asmar, Wang-Kong Tse. 2021-05-26. Impurity Screening and Friedel Oscillations in Floquet-driven Two-dimensional Metals. https://doi.org/10.1088/1361-648x%2Fac709d

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