Testing the Elliott-Yafet spin-relaxation mechanism in KC8: A model system of biased graphene

Temperature-dependent electron spin resonance (ESR) measurements are reported on stage-1 potassium-doped graphite, a model system of biased graphene. The ESR linewidth is nearly isotropic, and although the g factor has a sizable anisotropy, its majority is shown to arise due to macroscopic magnetization. Even though the homogeneous ESR linewidth shows an unusual, nonlinear temperature dependence, it appears to be proportional to the resistivity which is a quadratic function of the temperature. These observations suggests the validity of the Elliott-Yafet relaxation mechanism in KC8 and allows us to place KC8 on the empirical Beuneu-Monod plot among ordinary elemental metals.