A PHOTOEMISSION AND INVERSE-PHOTOEMISSION STUDY OF TRIGONAL TE

The valence-band and conduction-band densities of states (DOSS) of tri gonal Te have been investigated using ultraviolet photoemission and in verse-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 e V 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, narrowe r by about 1 eV than the experimental results. The Te 4d core-yield sp ectrum shows intense and sharp doublets at the 4d core-absorption thre shold. These structures are assigned to the spin-orbit doublets of the Te 4d core excitons with a comparatively long lifetime and a fairly l ocalized nature.