High-pressure modulation of breathing kagome lattice: Cascade of Lifshitz transitions and evolution of the electronic structure

TL;DR

This study demonstrates that applying pressure to Fe$_3$Sn$_2$ kagome metal tunes its electronic structure through Lifshitz transitions, revealing breathing distortion as a key control parameter for electronic correlations and electron dynamics.

Contribution

It reveals how external pressure modulates the breathing distortion in Fe$_3$Sn$_2$, inducing Lifshitz transitions and altering electronic correlations, a novel approach for controlling kagome metal properties.

Findings

Breathing distortion is suppressed around 15 GPa and reversed at higher pressures.

Pressure induces a series of Lifshitz transitions detected via optical spectroscopy.

Electronic correlations are enhanced as the kagome network becomes more regular.

Abstract

The interplay between electronic correlations, density wave orders, and magnetism gives rise to several fascinating phenomena. In recent years, kagome metals have emerged as an excellent platform for investigating these unique properties, which stem from their itinerant carriers arranged in a kagome lattice. Here, we show that electronic structure of the prototypical kagome metal, Fe$_3$Sn$_2$, can be tailored by manipulating the breathing distortion of its kagome lattice with external pressure. The breathing distortion is suppressed around 15 GPa and reversed at higher pressures. These changes lead to a series of Lifshitz transitions that we detect using broadband and transient optical spectroscopy. Remarkably, the strength of the electronic correlations and the tendency to carrier localization are enhanced as the kagome network becomes more regular, suggesting that breathing distortion can be a unique control parameter for the microscopic regime of the kagome metals and their electron dynamics.