Electronic Band Structure of Cubic HgS

Abstract

The electronic band structure of all II—VI compounds which crystallize in the sphalerite (zinc blende) structure has been investigated long time ago and is well known. The only exception could be the cubic modification of mercury sulfide (J -HgS). The reason is that due to its metastable character and significant problems with the crystal growth the bulk big size crystals of β-HgS have never been obtained. The investigations of the physical properties of this material were limited to the studies of the thin evaporated slabs, very small size pure policrystals, greater, but containing high concentration of different impurities, natural policrystals or the mixed crystals with Cd, Zn, Se or Te. It has been verified that β-HgS is a narrow-gap semiconductor with an inverted band structure [1]. However, the only attempt of the electronic band structure investigations in the whole Brillouin zone by means of the ultraviolet reflectivity measurements was limited to the studies of the good quality thin evaporated slabs [2]. The results of the β-HgS band structure calculations have also been published [3, 4]. The recently grown big size cubic HgS crystals stabilized by mercury sulfide doping with transition metal impurities [5] opened new possibility in electronic band structure investigations of the material under consideration. It was possible to investigate trends resulting from the measurements performed on different mixed crystals grown on the basis of HgS. For the reflectivity studies two systems have been chosen: semimagnetic semiconductor Hg1x FexS and the mixed crystal with two anions HgSe1y Sy . It is believed that the S solubility limit in HgSe is about 80%, the Fe solubility limit in HgS is not known up to now. Hg1x Fex S mixed crystals containing up to few percent of iron and HgSe1y Sy compounds in the composition range