Hidden electronic phase in strained few-layer 1T-TaS2

TL;DR

This study reveals a hidden electronic phase in strained few-layer 1T-TaS2, showing coexistence of insulating and metallic regions influenced by strain, with implications for understanding layered van der Waals materials.

Contribution

It demonstrates the impact of strain on the electronic ground state and uncovers the coexistence of phases within the charge density wave state of 1T-TaS2.

Findings

Coexistence of insulating and metallic phases within 1T-TaS2.

Strain can collapse the Mott gap in the material.

Electronic ground state is highly sensitive to inter-layer coupling.

Abstract

Layered van der Waals materials are exciting as they often host multiple, competing electronic phases. This article reports experimental observation of the co-existence of insulating and metallic phases deep within the commensurate charge density wave phase in high-quality devices of few-layer 1T-TaS2. Through detailed conductance fluctuation spectroscopy of the electronic ground state, we establish that the mixed-phase consists of insulating regions surrounded by one-dimensional metallic domain walls. We show that the electronic ground state of 1T-TaS2 can be affected drastically by strain, eventually leading to the collapse of the Mott gap in the commensurate charge density wave phase. Our study resolves an outstanding question, namely the effect of the inter-layer coupling strength on the electronic phases in layered van der Waals materials.