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arXiv · 2101.03048

Observation of the charge density wave collective mode in the infrared optical response of VSe$_2$

Xuanbo Feng·Jans Henke·Corentin Morice·Charles J. Sayers·Enrico Da Como·Jasper van Wezel·Erik van Heumen
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Abstract

We present a detailed study of the bulk electronic structure of high quality VSe$_{2}$ single crystals using optical spectroscopy. Upon entering the charge density wave phase below the critical temperature of 112 K, the optical conductivity of VSe$_2$ undergoes a significant rearrangement. A Drude response present above the critical temperature is suppressed while a new interband transition appears around 0.07\,eV. From our analysis, we estimate that part of the spectral weight of the Drude response is transferred to a collective mode of the CDW phase. The remaining normal state charge dynamics appears to become strongly damped by interactions with the lattice as evidenced by a mass enhancement factor m$^{*}$/m$\approx$3. In addition to the changes taking place in the electronic structure, we observe the emergence of infrared active phonons below the critical temperature associated with the 4a x 4a lattice reconstruction.

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Xuanbo Feng, Jans Henke, Corentin Morice, Charles J. Sayers, Enrico Da Como, Jasper van Wezel, Erik van Heumen. 2021-01-08. Observation of the charge density wave collective mode in the infrared optical response of VSe$_2$. https://doi.org/10.1103/physrevb.104.165134

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