Quasilinear quantum magnetoresistance in pressure-induced nonsymmorphic superconductor CrAs

TL;DR

This study reports a large, non-saturating quasilinear magnetoresistance in pressure-induced superconductor CrAs, caused by nonsymmorphic symmetry-protected band crossing and magnetic fluctuations, revealing novel electron transport behavior.

Contribution

It uncovers a new mechanism for quasilinear magnetoresistance linked to nonsymmorphic symmetry and magnetic fluctuations in a strongly correlated superconductor.

Findings

Large, non-saturating magnetoresistance observed up to 14 T

Magnetoresistance arises from nonsymmorphic symmetry-protected band crossing

Magnetoresistance linked to magnetic fluctuations near quantum phase transition

Abstract

In conventional metals, modification of electron trajectories under magnetic field gives rise to a magnetoresistance that varies quadratically at low field, followed by a saturation at high field for closed orbits on the Fermi surface. Deviations from the conventional behaviour, e.g. the observation of a linear magnetoresistance, or a non-saturating magnetoresistance, have been attributed to exotic electron scattering mechanisms. Recently, linear magnetoresistance has been observed in many Dirac materials, in which the electron-electron correlation is relatively weak. The strongly correlated helimagnet CrAs undergoes a quantum phase transition to a nonmagnetic superconductor under pressure. Near the magnetic instability, we observe a large and non-saturating quasilinear magnetoresistance from the upper critical field to 14 T at low temperatures. We show that the quasilinear magnetoresistance arises from an intricate interplay between a nontrivial band crossing protected by nonsymmorphic crystal symmetry and strong magnetic fluctuations