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arXiv · 2009.00987

Experimental Evidence of Stable 2$H$ Phase on the Surface of Layered 1$T'$-TaTe$_2$

Indrani Kar·Kapildeb Dolui·Luminita Harnagea·Y. Kushnirenko·G. Shipunov·N. C. Plumb·M. Shi·B. Büchner·S. Thirupathaiah
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Abstract

We report on the low-energy electronic structure of Tantalum ditelluride (1$T'$-TaTe$_2$), one of the charge density wave (CDW) materials from the group V transition metal dichalcogenides using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT). We find that the Fermi surface topology of TaTe$_2$ is quite complicated compared to its isovalent compounds such as TaS$_2$, TaSe$_2$, and isostructural compound NbTe$_2$. More importantly, we discover that the surface electronic structure of 1$T'$-TaTe$_2$ has more resemblance to the 2$H$-TaTe$_2$, while the bulk electronic structure has more resemblance to the hypothetical 1$T$-TaTe$_2$. These experimental observations are thoroughly compared with our DFT calculations performed on 1$T$-, 2$H$- and 2$H$ (monolayer)/1$T$- TaTe$_2$. We further notice that the Fermi surface topology is temperature independent up to 180 K, confirming that the 2$H$ phase on the surface is stable up to 180 K and the CDW order is not due to the Fermi surface nesting.

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Indrani Kar, Kapildeb Dolui, Luminita Harnagea, Y. Kushnirenko, G. Shipunov, N. C. Plumb, M. Shi, B. Büchner, S. Thirupathaiah. 2020-09-02. Experimental Evidence of Stable 2$H$ Phase on the Surface of Layered 1$T'$-TaTe$_2$. https://doi.org/10.1021/acs.jpcc.0c10517

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