Non-degenerate surface pair density wave in the Kagome superconductor CsV$_3$Sb$_5$ -- application to vestigial orders

TL;DR

This paper investigates the non-degenerate pair density wave states in the Kagome superconductor CsV$_3$Sb$_5$, exploring their implications for vestigial charge-4e phases and proposing STM experiments to distinguish these phases.

Contribution

It introduces the concept of a non-degenerate PDW in CsV$_3$Sb$_5$ and analyzes its role in vestigial charge-4e phases, offering experimental proposals.

Findings

PDW states share the same wavevector in the effective 2D Brillouin zone.

The non-degenerate PDW breaks specific surface symmetries.

Proposed STM experiments can distinguish vestigial phases.

Abstract

On the Sb-layer of the Kagome superconductor CsV$_3$Sb$_5$, pair density wave states have been observed. When the high-temperature charge orderings are treated as static backgrounds, these PDW states exhibit the same wavevector in the effective 2D Brillouin zone. Interestingly, these PDW states break the same symmetry on the surface. Considering the presence of this non-degenerate PDW, we investigate the implications for the possible existence of a vestigial charge-4e phase with a non-zero center-of-mass momentum. To distinguish between different vestigial phases, we propose scanning tunneling microscopy experiments. We aim to provide insights into the nature of the vestigial phases and their distinct characteristics in CsV$_3$Sb$_5$. This research sheds light on the interplay between PDW states, charge orderings, and superconductivity of the Kagome superconductor.