c axis electrical transport at the metamagnetic transition in the heavy-fermion superconductor UTe2 under pressure

TL;DR

This study investigates the anisotropic electrical resistivity and metamagnetic transition in the heavy-fermion superconductor UTe2 under pressure, revealing how resistivity behavior correlates with magnetic and structural phase changes.

Contribution

It provides new insights into the pressure and magnetic field dependence of resistivity and phase transitions in UTe2, highlighting the role of the temperature scale T^{max}_{ρ_c} in governing interactions.

Findings

Resistivity maximum along c-axis correlates with thermal expansion minimum.

Resistivity shows steplike changes at the metamagnetic transition.

Pressure suppresses superconductivity and induces antiferromagnetic order.

Abstract

The electrical resistivity of the unconventional superconductor UTe$_2$ shows very anisotropic behavior in the normal state depending on the current direction. In the present paper we show that the maximum in the resistivity $\rho_c$ for current applied along the $c$ axis at $T^{\rm max}_{\rho_c} \approx 14.75$~K follows the minimum in the thermal expansion $T_\alpha^\star$ along $b$ axis. Under a magnetic field applied along the $b$ axis, $T^{\rm max}_{\rho_c}$ can be tracked up to the critical point of the first order metamagnetic transition, which is located near 6~K and 34.5~T. Surprisingly, at the metamagnetic field $H_m$ the resistivity $\rho_c$ shows a steplike decrease while the resistivities $\rho_a$ and $\rho_b$, for current along the $a$ and $b$ axis, respectively, show a steplike increase. Under hydrostatic pressure $T^{\rm max}_{\rho_c}$ and $H_m$ decrease significantly up to the critical pressure $p_c$ at which superconductivity is suppressed and a long range antiferromagnetic order appears. We show that the phase diagram at different pressures can be scaled by $T^{\rm max}_{\rho_c}$ in field and temperature suggesting that this temperature scale is governing the main interactions in the normal state.