The nuclear spin relaxation time T1 is calculated taking account of the contributions from orbital currents of Dirac electrons. We consider a simple model of non-interacting Dirac electron gas in the three-dimensional bulk system. The obtained result shows T3 dependence of 1/T1 at temperatures T above the energy gap. This temperature dependence agrees qualitatively with the recent β-NMR experiment on the bulk of the topological insulator Bi0.9Sb0.1.
@article{arxiv.1705.06866,
title = {Nuclear Spin Relaxation Time due to the Orbital Currents in Dirac Electron Systems},
author = {Tomoki Hirosawa and Hideaki Maebashi and Masao Ogata},
journal= {arXiv preprint arXiv:1705.06866},
year = {2017}
}