Identification of the Mott insulating CDW state in 1T-TaS 2

Physical Review Letters 126 , 196406 (2021)

Identification of the Mott insulating CDW state in 1T-TaS 2

Dongbin Shin, Nicolas Tancogne-Dejean, Jin Zhang, Mahmut Sait Okyay, Angel Rubio, Noejung Park

We investigate the low-temperature charge-density-wave (CDW) state of bulk TaS 2 with a fully self-consistent DFT+U approach, over which the controversy has remained unresolved regarding the out-of-plane metallic band. By examining the innate structure of the Hubbard U potential, we reveal that the conventional use of atomic-orbital basis could seriously misevaluate the electron correlation in the CDW state. By adopting a generalized basis, covering the whole David star, we successfully reproduce the Mott insulating nature with the layer-by-layer antiferromagnetic order. Similar consideration should be applied for description of the electron correlation in molecular solid.

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We further acknowledge nancial support from the European Research Council (ERC- 2015-AdG-694097), the Cluster of Excellence 'CUI: Advanced Imaging of Matter' of the Deutsche Forschungsgemeinschaft (DFG) - EXC 2056 - project ID 390715994, Grupos Con- solidados (IT1249-19), and SFB925 "Light induced dynamics and control of correlated quan- tum systems". D.S. is supported by Alexander von Humboldt Foundation. N.P. is supported by National Research Foundation of Korea (NRF-2019R1A2C2089332). J.Z. acknowledges funding received from the European Union Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant Agreement 886291 (PeSD-NeSL).

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