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 5d3z2−r2 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 1T-TaS2 monolayer may pave a new way to study the exciton physics, exciton-polaron coupling, and potential applications for its exciton luminescence.
@article{arxiv.1407.1407,
title = {Orbital density wave order and electronic correlation driven insulating 1T-TaS2 monolayer},
author = {Xiang-Long Yu and Da-Yong Liu and Ting Jia and H. -Q. Lin and Liang-Jian Zou},
journal= {arXiv preprint arXiv:1407.1407},
year = {2021}
}