Surface Electric-Field—Induced Raman Scattering in PbTe and SnTe

Abstract

Electric-field-induced scattering by normally Raman-inactive LO phonons is observed in the IV-VI-compound (NaCl structure) semiconductors PbTe and SnTe with Pb films on $p$-type samples to induce energy-band bending. The observed Raman peaks correspond to unscreened $q\approx 0$ LO phonons. A discussion of the mechanisms contributing to the surface field-induced Raman scattering in these materials is presented.