Zoology of domain walls in quasi-2D correlated charge density wave of 1T-TaS2

TL;DR

This study combines experimental and theoretical methods to elucidate the atomic and electronic structures of domain walls in 1T-TaS2, revealing their diverse in-gap states and potential for functional engineering in correlated materials.

Contribution

It provides a detailed atomic and electronic characterization of various domain walls in 1T-TaS2 using STM and DFT, advancing understanding of their roles in quantum phases.

Findings

Domain walls exhibit various in-gap states within the Mott gap.

Metallic states are present only in specific types of domain walls.

Systematic analysis highlights the importance of structural relaxation, electron correlation, and charge transfer.

Abstract

Domain walls in correlated charge density wave compounds such as 1T-TaS2 can have distinct localized states which govern physical properties and functionalities of emerging quantum phases. However, detailed atomic and electronic structures of domain walls have largely been elusive. We identify using scanning tunneling microscope and density functional theory calculations the atomic and electronic structures for a plethora of discommensuration domain walls in 1T-TaS2 quenched metastably with nanoscale domain wall networks. The domain walls exhibit various in-gap states within the Mott gap but metallic states appear in only particular types of domain walls. A systematic understanding of the domain-wall electronic property requests not only the electron counting but also including various intertwined interactions such as structural relaxation, electron correlation, and charge transfer. This work guides the domain wall engineering of the functionality in correlated van der Waals materials.