Fe 3d Contribution to the Valence Band of Cubic Hg_1-xFe_xS - Resonant Photoemission Study

Abstract

Resonant photoemission spectra of cubic Ηg0.94Fe0.06S were measured for photoii energies near to the energy of intra atomic Fe 3p6 3d6 -^ 3p 5 3d 7 transition. The difference between the spectra taken at resonance and antiresonance is presented as a measure of the energy distribution of Fe 3d derived states. The results obtained show that Fe 3d states contribute to the whole valence band with a distinct structure appearing at the band edge.PACS numbers: 79.60.-i Many of the diluted magnetic semiconduction (DMS) based on II-VI compounds have been extensively investigated since the 70s. Their electric, magnetic and optical properties were determined and band stuctures described [1][2][3][4][5]. However, this is still not the case for those solid solutions which would contain mercury sulphide as a non magnetic component. This compound is an exception among the other, tetrahedrally bonded, members of the II-VI family. Its natural form (α-HgS) is a wide gap semiconductor of a cinnabar crystal lattice. The cubic modification of mercury sulphide, β-ΗgS, is stable at above 550 Κ but it transforms upon cooling into α-ΗgS [6]. Thus, big size, bulk monocrystals of cubic HgS have not been available to experimentation until quite recently. Some information about crystal stucture and electronic properties was obtained from experiments performed for a powder produced by chemical precipitation [7], a natural polycrystalline material highly doped with Fe (metacinnabar) [8], or vacuum-evaporated thin films [7].However, a technique of stabilization of the cubic lattice in big monocrystals of HgS grown by means of an equilibrium method has been recently proposed [9]. It is based on doping the crystals with a transition metal (e.g. Fe, Co) or selenium. That achievement made it possible to investigate further properties of β-ΗgS with prospects to compare the results with those known for HgTe and HgSe as well as for the cinnabar form of HgS. Moreover, a new group of solid solutions (DMS, among others) has been obtained. The opportunity arose to fjll the gap in the set of data concerning properties of II-VI based diluted magnetic semiconductors.(791)