Evolution toward Quantum Critical End Point in UGe_2

TL;DR

This study investigates the electronic and magnetic phase transitions in UGe_2 under pressure and magnetic field, revealing Fermi surface changes and scattering modifications near the quantum critical end point, with experimental results compared to theory.

Contribution

It provides experimental evidence of Fermi surface evolution and scattering behavior near the quantum critical end point in UGe_2, advancing understanding of ferromagnetic quantum criticality.

Findings

Hall resistivity detects first order metamagnetic transition

Fermi surface changes observed near QCEP

Inelastic scattering behavior is strongly modified near QCEP

Abstract

We report on Hall resistivity and electrical resistivity measurements under pressure and magnetic field in UGe_2 with ferromagnetic (FM) tricriticality. The Hall resistivity sensitively detects the first order metamagnetic transition from a paramagnetic (PM) phase to a FM phase in a large pressure range almost up to the quantum critical end point (QCEP). The drastic change in the Fermi surface at the PM-FM transition is detected up to the vicinity of the QCEP, while a strong modification in the field variation of the inelastic scattering between electrons is observed toward the QCEP. The comparison with the theoretical predictions is made.