Effect of s – d Exchange with an Itinerant Carrier in a GaMnAs/Ga_0.4 Al_0.6 As Quantum Dot: Effects of Magnetic Field and Spatial Confinement

Abstract

Magnetic field induced hydrogenic donor binding energy as a function of dot radius in a GaMnAs/Ga 0.4 Al 0.6 As quantum dot is calculated including the exchange interaction of Mn alloy content with an itinerant carrier. Calculations are performed by varying its dot radius, for various Mn incorporation in GaMnAs material within a single band effective mass approximation using variational method. The spin polaronic energy of donor impurity for different Mn 2+ is evaluated for different dot radii using a mean field theory in the presence of magnetic field strength. The effective g-factor of conduction band electron with the geometrical confinement is computed in the influence of magnetic field. The exchange coupling constant is calculated for various magnetic field. The results show that the s-d exchange interaction in the GaMnAs/Ga 0.4 Al 0.6 As quantum dot has a strong dependence on spatial confinement and the Mn alloy content. The magnetic confinement is dominant for larger dot sizes whereas the Mn alloy content has more pronounced for the smaller dots. The g-factor of conduction band electrons is considerably different from the free electron value. Our results are in good agreement with the other investigators.