Room temperature quantum metric effect in TbMn6Sn6

TL;DR

This study demonstrates a tunable, strong second-harmonic response at room temperature in TbMn6Sn6, driven by quantum metric effects, enabling potential practical quantum-geometry-based electronic devices.

Contribution

It reports the first observation of room-temperature quantum metric effects in a magnetic material, tunable via magnetic fields, advancing quantum geometry applications.

Findings

Room-temperature second-harmonic transport response in TbMn6Sn6.

Quantum metric governs the nonlinear response.

Magnetic field controls symmetry and response.

Abstract

Quantum geometry, including Berry curvature and the quantum metric, of the electronic Bloch bands has been studied via nonlinear responses in topological materials. Naturally, these material systems with intrinsic strong nonlinear responses also form the key component in nonlinear electronic devices. However, the previous reported quantum geometry effects are mainly observed at cryogenic temperatures, hindering their application in practical devices. Here we report the tuneable strong room-temperature second-harmonic transport response in a quantum magnet, TbMn6Sn6, which is governed by the quantum metric and can be tuned with applied magnetic fields. We show that around room temperature, which is close to the spontaneous spin-reorientation transition, the magnetic configurations, and therefore the related symmetry breaking phases, are easily controlled via magnetic fields. Our results also show that manipulation of the symmetries of the magnetic structure presents an effective route to tuneable quantum-geometry-based devices.