Impurity States in Semimagnetic Quantum Well Wire with Anisotropic Confinement along In-Plane Directions

Abstract

The effect of shape of the confining potential along two different confined directions in Quantum Well Wire (QWW) on the heavy hole binding energy bound to an acceptor impurity has been computed using variational principle in the envelope function and effective mass approximation. In order to elucidate the importance of choosing the material parameters like effective masses to get the reliable theoretical results since the effective masses play a crucial role in determining the carrier mobility especially in Quantum Wire structures, two different effective masses like constant effective mass which is isotropic and the directional dependent effective mass which is anisotropic, have been employed in solving the Schrödinger equation and the results have been compared. The shift in the Polaronic energy which arises due to the exchange interaction between the spin of the Mn²⁺ ion and the spin of the carrier has been computed by using mean field theory with modified Brillouin function. The observed results show that Quantum Size Effects are evidenced near the Wire size of ~30 Å and the binding energy is found to have enhanced values only for the case with isotropic effective mass than for the anisotropic effective mass. The magnetic tuning of the potential barrier leads to the probability for the quantum tunneling of the hole wavefunction into the barrier and thereby reduces the binding energy. The exchange interaction does not show its influence much on the Spin Polaronic Shift due to the competition between the square and parabolic confining potential in a QWW with such anisotropic confinement.