Three-dimensional electronic domain correlations in 1T-TaS2

TL;DR

This study uncovers the three-dimensional evolution of electronic domains in 1T-TaS2 across phase boundaries, revealing how stacking faults and layer dimerization influence its electronic properties and phase transitions.

Contribution

It introduces a combined X-ray diffraction and structure factor simulation approach to analyze 3D electronic domain behavior in 1T-TaS2, highlighting the role of stacking faults and domain structures.

Findings

Increased stacking faults near phase transitions.

Growth of dimerized layers in the commensurate phase.

Electronic domains mediate transport properties and intermediate phases.

Abstract

The interplay of nanoscale electronic domains underpins many emergent phenomena of quantum materials, including the competition between charge density waves (CDW) and superconductivity in high-Tc cuprates, or the storage of information in phase-change memory devices. Coupling to electronic domains provides an observable for pinpointing key interactions, e.g. affecting phase transitions. While the equilibrium phase diagram of 1T-TaS2 - characterized by unique transport properties and varying degrees of CDW commensurability - has been studied extensively, an understanding of how the electronic domains in the bulk behave across phase boundaries is lacking. We reveal the three-dimensional evolution of electronic domains in 1T-TaS2 using temperature-dependent X-ray diffraction and reciprocal space mapping, complemented by structure factor simulations based on the Hendricks-Teller method. With this methodology, we identify an increasing number of stacking faults near the phase transitions, and a growing fraction of dimerized layers in the commensurate phase upon cooling. We provide structural evidence that the CDW domains mediate the transport properties at phase boundaries, and that they also account for an anomalous intermediate electronic phase within the triclinic regime upon heating. As a paradigmatic material with potential in phase-change memory applications, our study underscores the importance of domain sizes and layer stacking in defining electronic behaviors of van der Waals materials.