Pressure dependence of the charge density wave in 1T-TaS2 and its relation to superconductivity

TL;DR

This study uses advanced x-ray diffraction to explore how pressure influences charge density waves in 1T-TaS2 and reveals their coexistence with superconductivity, challenging previous notions of spatial separation.

Contribution

It demonstrates that charge density waves coexist with superconductivity in 1T-TaS2 under pressure, providing new insights into their relationship in reciprocal space.

Findings

Charge density wave exists in the superconducting phase.

Superconductivity and charge density wave coexist macroscopically.

Charge density wave and superconducting gaps are in separate reciprocal space regions.

Abstract

We present a state-of-the-art x-ray diffraction study of the charge density wave order in 1T-TaS2 as a function of temperature and pressure. Our results prove that the charge density wave, which we characterize in terms of wave vector, amplitude and the coherence length, indeed exists in the superconducting region of the phase diagram. The data further imply that the ordered charge density wave structure as a whole becomes superconducting at low temperatures, i. e, superconductivity and charge density wave coexist on a macroscopic scale in real space. This result is fundamentally different from a previously proposed separation of superconducting and insulating regions in real space and, instead, provides evidence that the superconducting and the charge density wave gap exist in separate regions of reciprocal space.