Effects of concentration on magnetization in a diluted magnetic semiconductor quantum dot

Abstract

The donor bound spin polaron in a Cd 1− x Mn x Te quantum dot is investigated theoretically. Spin polaronic shifts are estimated using a mean field theory. Magnetization is calculated for various concentrations of Mn 2+ ions with the dot sizes. The lowest binding energies in a diluted magnetic semiconductor of a Cd 1− x Mn x Te quantum dot are also estimated. Using the effective mass approximation, calculations are presented with and without spatial dependent effective masses. It is found that (i) the lowest binding energy decreases with the dot radius (ii) position dependent mass gives larger binding energy for smaller dots (iii) the ionization energy becomes more when spin interaction energy is included (iv) variation of increase in ionization energy is sharper for smaller dots with increase in concentration and (v) the magnetization of Mn subsystem increases when concentration of Mn 2+ ions increases and it has appreciable changes for smaller dots.