Absolute negative mobility of charge carriers in diamond and interpretation of μSR experiments

A theoretical analysis is given to describe the evolution of the distribution function of non-equilibrium charge carriers, which were formed due to the capture of negative muon by a carbon atom. The electrons and holes thermalization by interaction with acoustic phonons is considered. Diffusion and mobility coefficients were calculated for non-equilibrium charge carriers in diamond at low medium temperatures (below 20 K) and the appearance of a negative mobility is predicted for some energies and temperatures. Results of numerical calculations of charged cloud evolution in diamond are presented. It is shown that at low temperatures the acceptor center mu B is rapidly formed in a paramagnetic state due to collecting of holes at the charged center. The results explain the experimental negative muon polarization dependence versus temperature. (c) 2005 Elsevier B.V. All rights reserved.