arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2009.00987cond-mat.mtrl-scicond-mat.mes-hall
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层状1 $T'$ - TaTe $_2$表面稳定2 $H$相的实验证据

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

摘要:

利用角分辨光电子能谱(ARPES)和密度泛函理论(DFT)研究了V族过渡金属二硫属化合物的电荷密度波(CDW)材料二碲化钽(1 $T'$ -TaTe $_2$)的低能电子结构.我们发现,与TaS $_2$,TaSe $_2$,NbTe $_2$等等价化合物相比,TaTe $_2$的费米面拓扑结构非常复杂.更重要的是,我们发现1 $T'$ -TaTe $_2$的表面电子结构与2 $H$ -TaTe $_2$更相似,而体电子结构与假设的1 $T$ -TaTe $_2$更相似.这些实验观测与我们对1 $T$ -、2 $H$ -和2 $H$(单层)/1 $T$ - TaTe $_2$进行的DFT计算进行了彻底的比较。我们进一步注意到,费米表面拓扑结构是温度无关的高达180 K,确认2 $H$相的表面上是稳定的高达180 K和CDW秩序不是由于费米表面嵌套。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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