Disrupted orbital order and the pseudo-gap in layered 1T-TaS$_2$

TL;DR

This study uses advanced DFT modeling to accurately reproduce the electronic band structure and pseudo-gap phenomena in layered 1T-TaS2, emphasizing the role of orbital order and interlayer interactions.

Contribution

The paper demonstrates that realistic DFT models can capture the pseudo-gap and orbital disorder effects in 1T-TaS2, highlighting the significance of interlayer interactions.

Findings

DFT models match experimental band structures

Pseudo-gap formation explained without strong correlations

Interlayer interactions crucial for electronic properties

Abstract

We present a state-of-the-art density functional theory (DFT) study which models crucial features of the partially disordered orbital order stacking in the prototypical layered transition metal dichalcogenide 1T-TaS2 . Our results not only show that DFT models with realistic assumptions about the orbital order perpendicular to the layers yield band structures which agree remarkably well with experiments. They also demonstrate that DFT correctly predicts the formation of an excitation pseudo-gap which is commonly attributed to Mott-Hubbard type electron-electron correlations. These results highlight the importance of interlayer interactions in layered transition metal dichalcogenides and serve as an intriguing example of how disorder within an electronic crystal can give rise to pseudo-gap features.