Magnetism and weak electronic correlations in Kagome metal ScV$_6$Sn$_6$

TL;DR

This study uses advanced theoretical methods to analyze the electronic correlations and magnetic properties of the Kagome metal ScV$_6$Sn$_6$, revealing weak correlations and no local magnetic moments, and suggesting Fermi surface nesting is not the main driver of its charge density wave phase.

Contribution

The paper provides a systematic DFT+DMFT analysis of ScV$_6$Sn$_6$, clarifying the weak correlation effects and the non-magnetic nature of its electronic state, which advances understanding of its CDW phase.

Findings

Static local spin susceptibility is temperature-independent.

Weak correlation strength indicated by mass enhancements.

Electronic correlations are not the main factor in CDW formation.

Abstract

As one class of typical quantum materials, Kagome metals in $A$V$_3$Sb$_5$($A$ = K, Rb, Cs) have attracted extensive attentions due to their interesting physical properties and different quantum phases of charge density wave (CDW), superconductivity and nontrivial topology. Recently, a new CDW phase in ScV$_6$Sn$_6$ was experimentally observed and inspired a wide study of the mechanism of driving force. To have a clear understanding of the correlation effect in the CDW phase in ScV$_6$Sn$_6$, we performed a systematic density functional theory plus dynamical mean field theory (DFT + DMFT) calculations. The resulting static local spin susceptibility is nearly independent of temperature, indicating the absence of local moment on atom V, in full agreement with experimental measurements. The mass enhancements of quasiparticles and bandwidth renormalizations near the Fermi level show a weak correlation strength in ScV$_6$Sn$_6$. In addition, the comparable mass enhancements of quasiparticles in ScV$_6$Sn$_6$ with CDW order and YV$_6$Sn$_6$ without CDW phase suggests that electronic correlations corresponding to Fermi surface nesting do not play the dominant role in the formation of CDW order in ScV$_6$Sn$_6$.