Field induced phases in UPt2Si2

TL;DR

This study investigates high magnetic field-induced phases in UPt2Si2, revealing new phases above the antiferromagnetic state and discussing their origins in Fermi surface effects and topological transitions.

Contribution

The paper provides the first extensive high-field characterization of UPt2Si2, identifying new phases and challenging previous models based on crystal electric field effects.

Findings

Metamagnetic transition at ~40 T along a axis.

Distinct anomalies in properties above ~24 T along c axis.

Identification of new high field phases above the AFM ground state.

Abstract

The tetragonal compound UPt2Si2 has been characterised as a moderately mass enhanced system with an antiferromagnetic ground state below T_N = 32 K. Here, we present an extensive study of the behavior in high magnetic fields. We have performed pulsed field magnetization and static field resistivity measurements on single crystalline samples UPt2Si2. Along the crystallographic a axis, at low temperatures, we find a metamagnetic-like transition in fields of the order 40 T, possibly indicating a first order transition. Along the crystallographic c axis, in magnetic fields of B>= ~24 T, we find distinct anomalies in both properties. From our analysis of the data we can distinguish new high field phases above the AFM ground state. We discuss the emergence of these new phases in the context of Fermi surface effects and the possible occurrence of a Lifshitz or electronic topological transition, this in contrast to previous modellings of UPt2Si2 based on crystal electric field effects.