Catastrophic Fermi surface reconstruction in the shape-memory alloy AuZn

TL;DR

This study observes a dramatic Fermi surface change in AuZn during its shape-memory transition, revealing intrinsic phase separation and microstructural effects influencing electron scattering.

Contribution

It provides direct experimental evidence of a catastrophic Fermi surface reconstruction associated with the shape-memory transition in AuZn.

Findings

Fermi surface reconstruction occurs at the shape-memory transition temperature.

Coexistence of two Fermi surfaces suggests phase separation.

Change in scattering mechanism linked to microstructure.

Abstract

AuZn undergoes a shape-memory transition at 67 K. The de Haas van Alphen effect persists to 100 K enabling the observation of a change in the quantum oscillation spectrum indicative of a catastrophic Fermi surface reconstruction at the transition. Coexistence of both Fermi surfaces at low temperatures is suggestive of an intrinsic phase separation in the bulk of the material. In addition, a Dingle analysis reveals a sharp change in the scattering mechanism at a threshold cyclotron radius, which we suggest to be related to the underlying microstructure that drives the shape-memory effect.