X-ray photoelectron study of NiAs-type MnTe

Electronic structure of NiAs-type MnTe (H-MnTe) has been studied by X-ray photoelectron spectroscopy (XPS). Among the core-level spectra, analysis of the Mn 2p XPS spectrum revealed a prevailing contribution of the Mn 2+ cationic state, accompanied by minor spectral component of low binding energy (BE) indicative of reduced-valence Mn q+ ions (0 < q < 1). The latter one was attributed to the Mn–Te bonds that were broken during mechanical cleaning (scraping) of crystal surface. Occurrence of the high-intensity satellite of Mn 2p 3/2 (Mn 2+-related) parent line confirmed that H-MnTe belongs to the class of charge-transfer compounds. Evidence of plasmon loss satellite in Mn 2p spectrum led to an estimate of the bulk plasmon energy in H-MnTe. The valence-band (VB) XPS spectrum of H-MnTe exhibited a well-pronounced structure of two peaks (at about 3.8 eV and 2.6 eV below VB maximum). Compared with the band theory [S.-H. Wei, A. Zunger, Phys. Rev. B 35 (1987) 2340] they were assigned to the predominant Mn 3d majority-spin contribution to the total VB density of states.