Inelastic Scattering of Tunneling Electrons by Localized Vibrational Modes in PbTep−nJunctions

Liquid-helium-temperature tunneling data for PbTe indium-doped $p-n$ junctions exhibit a series of sharp conductance increments with ∼5-mV spacing as well as the "zero-bias conductance minimum" and the LO-phonon shoulder at ∼13.8 mV. Indium-gallium alloyed junctions exhibit also a second series with ∼6.5-mV spacing. This periodic structure is attributed to the "inelastic scattering" of tunneling electrons by localized vibrational modes of the indium and gallium impurity atoms in the tunneling junction.