Francesco Petocchi^1*, Christopher W. Nicholson¹, Bjoern Salzmann¹, Diego Pasquier², Oleg Yazyev², Claude Monney¹, Philipp Werner^1*

1 Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland

2 Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1951 Sion, Valais, Switzerland

* Corresponding authors emails: francesco.petocchi@unifr.ch, philipp.werner@unifr.ch

DOI10.24435/materialscloud:v6-nk [version v1]

Publication date: Nov 18, 2022

How to cite this record

Francesco Petocchi, Christopher W. Nicholson, Bjoern Salzmann, Diego Pasquier, Oleg Yazyev, Claude Monney, Philipp Werner, Mott versus hybridization gap in the low-temperature phase of 1T-TaS₂, Materials Cloud Archive 2022.150 (2022), doi: 10.24435/materialscloud:v6-nk.

Description

We address the long-standing problem of the ground state of 1T-TaS₂ by computing the correlated electronic structure of stacked bilayers using the GW+EDMFT method. Depending on the surface termination, the semi-infinite uncorrelated system is either band insulating or exhibits a metallic surface state. For realistic values of the on-site and inter-site interactions, a Mott gap opens in the surface state, but it is smaller than the gap originating from the bilayer structure. Our results are consistent with recent scanning tunneling spectroscopy measurements for different terminating layers, and with our own photoemission measurements, which indicate the coexistence of spatial regions with different gaps in the electronic spectrum. By comparison to exact diagonalization data, we clarify the interplay between Mott insulating and band insulating behavior in this archetypal layered system.

Materials Cloud sections using this data

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Keywords

Transition metal dichalcogenides DMFT first principles MARVEL/DD5