Photoemission Investigation of the Band Structure of PbTe

Measurements of the spectral distribution of photoemissive quantum yield and the energy distribution of photoemitted electrons from PbTe for 5.0 eV<hν<11.5 eV are reported. The electron affinity is found to be 4.6±{}0.3 eV. Regions with high density of states are located 0.7 and 1.2 eV below the valence-band maximum and assigned to the (L₄⁺, L₅⁺) and L₆⁺ symmetry points, respectively. By using the photoemission data and Cardona and Greenaway's optical data, the L₆^- and (L₅^-, L₄^') conduction-band points are located approximately 1.3 eV above the valence-band maximum. A high-density point is found 2.4 eV below the valence-band maximum. Evidence is presented that this high-density point is not due solely to structure near the L point.