Electronic structure of HgSe(001) investigated by direct and inverse photoemission

Stimulated by recent photoemission results which suggest a positive fundame ntal energy gap in HgSe, we have investigated the electronic structure of m olecular beam epitaxially grown HgSe(001) c(2 x 2) layers by a combination of direct ultraviolet photoemission spectroscopy (UPS) and inverse (IPES) p hotoelectron spectroscopy. Our UPS results do not support the finding of ad ditional peaks above the valence band maximum (VBM) of Gawlik et al. [Phys. Rev. Lett. 78, 3165 (1997)]. A comparison of angle-integrated UPS and IPES spectra and nb initio calculated density of states of HgSe and HgTe demons trates dissimilar behavior of the two compounds in the dispersion of the co nduction bands between 0 and 2 eV above the VBM. Our results are compatible with the common view that HgSe is a semimetal.