Impact of S doping on the structural, electronic and magnetic properties of Cr n (n = 2 − 6) clusters

Abstract

The impact of sulphur doping on the geometrical and electronic properties of small chromium clusters with up to six atoms is investigated within the density functional theory in the generalized gradient approximation for exchange and correlation. Neutral and charged states are considered in order to analyze the behavior of the vertical ionization potential and adiabatic electron affinity as a function of cluster size. We find good agreement with experimental data for the above electronic indicators in the case of pure chromium clusters, and show that S doping enhances their absolute stability, without destroying for the smaller ones, or not completely for the larger ones, the dimerization pattern typical of small particles made of elements with exact half-band filling. Thus, the chromium skeleton is largely preserved in general. Moreover, S doping does not destroy the odd-even behavior of the electronic quantities either. We find lower relative stability in clusters with odd number of Cr atoms than in those with even number, while only odd-Cr clusters retain a total magnetic moment which results slightly quenched upon S doping. The moment of the anionic clusters remains unchanged upon doping. We show that doping with an S impurity is a way to increase the stability of small Cr nanoparticles, without substantially modifying their magnetic properties and other electronic indicators.