Disorder such as impurities and dislocations in Weyl semimetals (SMs) drives a quantum critical point (QCP) where the density of states at the Weyl point gains a non-zero value. Near the QCP, the asymptotic low energy singularities of physical quantities are controlled by the critical exponents ν and z. The nuclear spin-lattice relaxation rate, which originates from the hyperfine coupling between a nuclear spin and long-range orbital currents in Weyl fermion systems, shows intriguing critical behavior. Based on the self-consistent Born approximation for impurities, we study the nuclear spin-lattice relaxation rate 1/T1 due to the orbital currents in disordered Weyl SMs. We find that (T1T)−1∼E2/z at the QCP where E is the maximum of temperature T and chemical potential μ(T) relative to the Weyl point. This scaling behavior of (T1T)−1 is also confirmed by the self-consistent T-matrix approximation, where a remarkable temperature dependence of μ(T) could play an important role. We hope these results of (T1T)−1 will serve as an impetus for exploration of the disorder-driven quantum criticality in Weyl materials.
@article{arxiv.1912.11996,
title = {Nuclear spin relaxation rate near the disorder-driven quantum critical point in Weyl fermion systems},
author = {Tomoki Hirosawa and Hideaki Maebashi and Masao Ogata},
journal= {arXiv preprint arXiv:1912.11996},
year = {2020}
}