Low-Energy Electronic Structure in the Unconventional Charge-Ordered State of ScV$_6$Sn$_6$

TL;DR

This study investigates the electronic structure of ScV$_6$Sn$_6$ in its charge-ordered state, revealing minimal changes in ARPES but strong QPI features in STM, suggesting complex scattering mechanisms and similarities to other kagome materials.

Contribution

It provides the first detailed comparison of electronic properties in ScV$_6$Sn$_6$'s charge-ordered state using ARPES and STM, highlighting the role of momentum-dependent scattering.

Findings

ARPES shows minimal electronic structure change post-CDW

STM QPI reveals strong dispersing features related to CDW

Bands near van Hove singularities are most affected by CDW

Abstract

Kagome vanadates {\it A}V$_3$Sb$_5$ display unusual low-temperature electronic properties including charge density waves (CDW), whose microscopic origin remains unsettled. Recently, CDW order has been discovered in a new material ScV$_6$Sn$_6$, providing an opportunity to explore whether the onset of CDW leads to unusual electronic properties. Here, we study this question using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM). The ARPES measurements show minimal changes to the electronic structure after the onset of CDW. However, STM quasiparticle interference (QPI) measurements show strong dispersing features related to the CDW ordering vectors. A plausible explanation is the presence of a strong momentum-dependent scattering potential peaked at the CDW wavevector, associated with the existence of competing CDW instabilities. Our STM results further indicate that the bands most affected by the CDW are near vHS, analogous to the case of {\it A}V$_3$Sb$_5$ despite very different CDW wavevectors.