On Sharp Enhancement of Effective Mass of Quasiparticles and Coefficient of T^{2} Term of Resistivity around First-Order Metamagnetic Transition Observed in UTe_{2}

TL;DR

This paper provides a theoretical explanation for the enhancement of quasiparticle effective mass and resistivity coefficient near the first-order metamagnetic transition in UTe₂, attributing it to ferromagnetic spin fluctuations within a Landau theory framework.

Contribution

It introduces a Landau theory-based model that explains the enhancement of effective mass and resistivity near the metamagnetic transition in UTe₂, aligning with experimental findings.

Findings

Enhanced ferromagnetic spin fluctuations increase quasiparticle effective mass.

The model reproduces the observed scaling behavior of resistivity.

The theory aligns with experimental data on UTe₂'s metamagnetic transition.

Abstract

The mechanism underlying the enhancement of the Sommerfeld coefficient of quasiparticles at the first-order metamagnetic transition in UTe_2, reported by Miyake et al. in J. Phys. Soc. Jpn. 88, 063706 (2019), is discussed theoretically by taking into account the ferromagnetic order-parameter fluctuations on the basis of the Landau theory of phase transition. We find that the enhanced ferromagnetic spin fluctuation gives rise to the enhancement of the effective mass of the quasiparticles or the Sommerfeld coefficient \gamma,which is consistent with the experimental observations. At the same time, the Kadowaki-Woods type scaling around the metamagnetic transition, reported by Imajo et al.in J. Phys. Soc. Jpn. 88, 083705 (2019) and Knafo et al. in J. Phys. Soc. Jpn. 88, 063705 (2019), is also understood semi-quantitatively by assuming reasonable values of parameters of Landau-type free energy reproducing key quantities characterizing the metamagnetic transition.