Frustrated Ising charge correlations in the kagome metal ScV$_6$Sn$_6$

TL;DR

This paper investigates the short-range charge correlations in the kagome metal ScV$_6$Sn$_6$, revealing a frustrated zig-zag phase driven by Ising-like interactions, which preempt long-range charge order at high temperatures.

Contribution

It provides the first real-space and reciprocal-space analysis of high-temperature charge correlations, linking them to a frustrated Ising model in a kagome metal.

Findings

Diffuse scattering indicates frustrated charge correlations above $T_{CO}$

Identifies a high-temperature zig-zag phase with Ising-like interactions

Models explain the origin of frustration in charge order

Abstract

Here we resolve the real-space nature of the high-temperature, short-range charge correlations in the kagome metal ScV$_6$Sn$_6$. Diffuse scattering appears along a frustrated wave vector $\textbf{q}_H=(\frac{1}{3},\frac{1}{3},\frac{1}{2})$ at temperatures far exceeding the charge order transition $T_{CO}=92~\mathrm{K}$, preempting long-range charge order with wave vectors along $\textbf{q}_{\bar{K}}=(\frac{1}{3},\frac{1}{3},\frac{1}{3})$. Using a combination of real space and reciprocal space analysis, we resolve the nature of the interactions between the primary out-of-plane Sc-Sn chain instability and the secondary strain-mediated distortion of the in-plane V kagome network. A minimal model of the diffuse scattering data reveals a high-temperature, short-ranged "zig-zag" phase of in-plane correlations that maps to a frustrated triangular lattice Ising model with antiferromagnetic interactions and provides a real-space understanding of the origin of frustrated charge order in this material.