Temperature and Magnetic Field Dependence of Muonic Knight Shifts in Semimetals

Abstract
The muon spin precession frequencies in the semimetals As, Sb and Bi have been studied as function of temperature and applied magnetic field. In Sb an anomalously large, temperature dependent and anisotropic Knight shift was found (at T = 2 K, Kiso = 0.9%, Kax = 0.3%). The shift is small above 100 K. The results are qualitatively discussed in terms of two models: (i) a shallow donor state and (ii) as partly bound electron states at an impurity charge in a metal. This large Knight shift is not found in As and Bi.