POLARIZED X-RAY-ABSORPTION SPECTRA AND ELECTRONIC-STRUCTURE OF MOLYBDENITE (2H-MOS2)

Polarized S K- and L-edge, Mo L(3)- and L(2)-edge x-ray absorption nea r-edge structure (XANES) of natural molybdenite (H-MoS2) have been mea sured with synchrotron radiation. These results are qualitatively inte rpreted using the energy band model of molybdenite and provide importa nt information on the unoccupied states of molybdenite. The valence ba nd (VB) maximum of molybdenite is characterized by fully occupied Mo 4 d(z2),and the conduction band (CB) minimum of molybdenite is characte rized by unoccupied Mo 4d states. The unoccupied Mo 4d band is split i nto two sub-bands, designated ignated as t(2g)(-)/t(2g)(+) and e(g)(-) /e(g)(+) sets. Although the relative energy of these two sets are diff icult to be evaluated, probably the former has the lower energy than t he latter, both two sets have the combination wave functions of the ot her unoccupied Mo 4d components, rather than the simple 4d(x2-y2) and 4d(xy) states. The unoccupied Mo 4d sub-bands contain significant DOS of both S 3p- and 3 s-like states, indicating strong hybridization wit h S 3 s and 3p states. In the lower energy sub-band, the DOS of the S p(z)- and p(x,y)-like states are very similar. However, in the higher energy sub-band, the DOS of the S 3p(x,y)-like state is lower than tha t of the S 3p(z) state. Polarized S K-edge XANES also reveal the featu res of antibonding S p(z)- and p(x,y)-like states in molybdenite. The feature assigned to the S 3p(z)-like states is stronger and sharper, a nd shifts to lower energy by about 2 eV relative to that for the S 3p( x,y)-like states.