The mobility of ${\mathrm{Pb}}_{1-x}{\mathrm{Sn}}_x\mathrm{Se}$ alloys for $0\le x\le 0.16$ has been measured under a hydrostatic pressure of up to 14 kbars at liquid-helium and -nitrogen temperatures. The experimental results are interpreted using the band parameters calculated from a $\overrightarrow{\mathrm{k}}·\overrightarrow{\pi }$ theory about the $L$ point of the Brillouin zone, together with an energy-dependent relaxation time for various mechanisms which appear at low temperatures. This theoretical interpretation allows us to determine the dominant mechanisms which limit the mobility in these salts and to evaluate the parameters which characterize the diffusion processes.

• Received 23 February 1973

DOI:https://doi.org/10.1103/PhysRevB.8.4686