A photoemission and inverse-photoemission study of trigonal Te

Abstract

The valence-band and conduction-band densities of states (DOSS) of trigonal Te have been investigated using ultraviolet photoemission and inverse-photoemission spectroscopy. We find structures at -0.8, -1.7, -3.6, -4.6, -10.6 and -12.8 eV, and at 1.4, 2.1, 2.7, 4.7, 6.1 and 9.5 eV with respect to the valence-band maximum. Relative energy positions of structures within the valence bands and those within the conduction bands are in good agreement with those in the calculated DOSS on the basis of the empirical pseudopotential theory. Separation between the theoretical valence-band and conduction-band DOSS is, however, narrower by about 1 eV than the experimental results. The Te 4d core-yield spectrum shows intense and sharp doublets at the 4d core-absorption threshold. These structures are assigned to the spin-orbit doublets of the Te 4d core excitons with a comparatively long lifetime and a fairly localized nature.