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arXiv · 1407.1407

Orbital density wave order and electronic correlation driven insulating 1T-TaS2 monolayer

Xiang-Long Yu·Da-Yong Liu·Ting Jia·H. -Q. Lin·Liang-Jian Zou
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Abstract

We present the orbital resolved electronic properties of structurally distorted 1T-TaS2 monolayers. After optimizing the crystal structures, we obtain the lattice parameters and atomic positions in the star-of-David structure, and show the low-temperature band structures of distorted bulk are consistent with recent angle resolved photoemission spectroscopy (ARPES) data. We further clearly demonstrate that $5d$ electrons of Ta form ordered orbital-density-wave (ODW) state with dominant $5d_{3{z}^2-{r}^2}$ character in central Ta, driving the one-dimensional metallic state in paramagnetic bulk and half-filled insulator in monolayer. Meanwhile, the star-of-David distortion in monolayers favors charge density wave and the flat band stabilizes ferromagnetic density wave of Ta spins with the same wavevector of ODW 4/13 b_1+1/13 b2. We propose that $1$T-TaS$_{2}$ monolayer may pave a new way to study the exciton physics, exciton-polaron coupling, and potential applications for its exciton luminescence.

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Xiang-Long Yu, Da-Yong Liu, Ting Jia, H. -Q. Lin, Liang-Jian Zou. 2014-07-05. Orbital density wave order and electronic correlation driven insulating 1T-TaS2 monolayer. https://doi.org/10.1103/physrevb.96.125138

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