Field induced Lifshitz transition in UPt$_2$Si$_2$: Fermi surface under extreme conditions

TL;DR

This study investigates the Fermi surface evolution in UPt$_2$Si$_2$ under high magnetic fields, revealing a field-induced Lifshitz transition with evidence from magnetotransport and band structure calculations.

Contribution

It provides experimental evidence for a Lifshitz transition in UPt$_2$Si$_2$ induced by magnetic fields, highlighting the role of electron interactions in topological Fermi surface changes.

Findings

Observation of strong Hall effect changes at phase boundaries

Evidence for a discontinuous Lifshitz transition

History dependence indicating electron interaction effects

Abstract

We have measured Hall effect, magnetotransport and magnetostriction on the field induced phases of single crystalline UPt$_2$Si$_2$ in magnetic fields up to 60\,T at temperatures down to 50\,mK. For the magnetic field applied along the $c$ axis we observe strong changes in the Hall effect at the phase boundaries. From a comparison to band structure calculations utilizing the concept of a dual nature of the uranium 5$f$ electrons, we find evidence for field induced topological changes of the Fermi surface due to at least one Lifshitz transition. Furthermore, we find a unique history dependence of the magnetotransport and magnetostriction data, indicating that the Lifshitz type transition is of a discontinuous nature, as predicted for interacting electron systems.