Spatial anisotropy of the exchange integrals in Mn-doped wurtzite-type semiconductors

A. M. Daré,
A. Savoyant,
S. D"Ambrosio,
A. Stepanov

Інститут проблем матеріалознавства ім. І. М. Францевича НАН України , вул. Кржижановського 3, Київ, 03142, Україна
Phys. Rev. B - Меріленд, США: Американське Фізичне Суспільство (APS), 2011, #84


We propose an alternative explanation, as compared to one reported in the literature, to the experimentally observed spatial anisotropy ξ=ΔJ1/J1in (ΔJ1=J1in-J1out) of the nearest neighbor exchange integral J1 in Mn-doped semiconductors with the wurtzite structure. We show that the main contribution to ξ is ferromagnetic and comes from a looped exchange path which involves two distinct anions. A comparison between our calculations, that use the results of photoemission spectroscopy as input parameters, and the available data for three wurtzite materials, CdS:Mn, CdSe:Mn, and ZnO:Mn, shows a good quantitative agreement between theory and experiment in the case of cadmium compounds and only a qualitative one in the case of ZnO:Mn.