Magnetomagnon resonances and oscillations of conductivity in diluted magnetic semiconductor quantum wires

Abstract

We set up a theory of magnetomagnon resonances in diluted magnetic semiconductor quantum wires in the case of electron-magnon scattering. The magnetoconductivity σxx is calculated using the usual Kubo formula. We found that for a nondegenerate statistics of quasi-one-dimensional electron gas σxx shows oscillatory behavior characteristic of structures presenting manifestations of the size quantization effect in the presence of a quantizing magnetic field. Moreover, magnetomagnon resonances are predicted in the σxx behavior as function of the electron cyclotron frequency. Another contribution to the conductivity σpc, which is caused by the current carried by electron motion affected by the confinement potential, is calculated. As the confinement potential increases, for a fixed magnetic field value, σpc decreases steeply similar to the case of GaAs quantum wires. For typical parameters of a Ga1−xMnxAs quantum wire we find σxx=10−9S for a magnetic field of 10T and temperature T=20K. This magnon effect is two orders of magnitude greater than the magnetoconductivity due to phonons as reported in the literature thereby implying that in diluted magnetic semiconductor Ga1−xMnxAs quantum wires the exchange interaction is the main electron interaction channel.