Field-dependent electrical conductivity in disordered ${\mathrm{Ge}}_{1-x}{\mathrm{Au}}_x$ alloys

The electric-field-dependent conductivity was studied on ${\mathrm{Ge}}_{1-x}{\mathrm{Au}}_x$ alloys near the metal-insulator transition. We have been able to rule out trivial heating effects, and our experiments are described in terms of electron heating. Our findings are in good agreement with theories which discuss electron-phonon relaxation time effects.