Electronic correlation effects and orbital order in the layered compound 1T-TaS2
Abstract
To account for the low-temperature insulating nature in commensurate CDW (CCDW) ordered bulk 1T-TaS2, the Mott insulator, the electron-phonon coupling or Fermi surface nesting and the disorder mechanisms were proposed and have been debated for more than thirty years. In this work we present the electronic structures and orbital-resolved electronic properties of structurally distorted 1T-TaS2 bulk and monolayer within DFT approaches. The relaxed CCDW structure shows that thirteen Ta atoms condense into a star-of-David cluster, accompanied by a buckling of neighboring S planes. Through detailed analyses to the orbital characters near the Fermi level, we show that there exists an orbital-density-wave (ODW) order, which is predominantly contributed by Ta-5d3z2-r2 orbital in the central Ta of the star-of-David cluster. We further demonstrate that the structural distortion, together with the Coulomb interaction, stabilizes the CCDW insulating ground state with an ODW order. The results obtained from DMFT confirm the role of the electronic correlation. Moreover, such an ODW ground state favors an intralayer ferromagnetic order in bulk and monolayer 1T-TaS2, and an interlayer antiferromagnetic order in bulk.
Work supported by NSF of China under Grants No. 11274310, 11574315 and 11604142.- Publication:
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APS March Meeting Abstracts
- Pub Date:
- 2018
- Bibcode:
- 2018APS..MARL45010Z