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Optical study of the charge-density-wave mechanism in 2$H$-TaS$_2$ and Na$_x$TaS$_2$

W. Z. Hu·G. Li·J. Yan·H. H. Wen·G. Wu·X. H. Chen·N. L. Wang
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Abstract

We report an optical study of transition metal dichalcogenide 2$H$-TaS$_2$ and Na intercalated superconductor Na$_x$TaS$_2$ over a broad frequency range at various temperatures. A clear gap feature was observed for 2$H$-TaS$_2$ when it undergoes a CDW transition. The existence of a Drude component in $σ$$_1$($ω$) below T$_{CDW}$ indicates that the Fermi surface of 2$H$-TaS$_2$ is only partially gapped in CDW state. The spectral evolution of two different Na$_x$TaS$_2$ crystals further confirms that the partial gap structure observed in 2$H$-TaS$_2$ has a CDW origin. The CDW mechanism for 2$H$-TaS$_2$, the competition between CDW and superconductivity in Na$_x$TaS$_2$ system are discussed.

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W. Z. Hu, G. Li, J. Yan, H. H. Wen, G. Wu, X. H. Chen, N. L. Wang. 2007-04-03. Optical study of the charge-density-wave mechanism in 2$H$-TaS$_2$ and Na$_x$TaS$_2$. https://doi.org/10.1103/physrevb.76.045103

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