Tunneling Ionization of AutolocalizedDX−Centers in Terahertz Fields

Tunneling ionization of ${\mathrm{DX}}^{-}$ centers in ${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{Sb}$ has been observed in terahertz radiation fields. Tunneling times have been measured for autolocalized and on-site deep impurities. It is shown that in one case the tunneling time is smaller and in the other larger than the reciprocal temperature multiplied by a universal constant due to the different tunneling trajectories. This allows one to distinguish in a direct way between the two types of configuration potentials of impurities.