Atomistic tight-binding investigations of Mn-doped ZnSe nanocrystal: Electronic, optical and magnetic characteristics

Abstract

Using the atomistic tight-binding theory with sp-d exchange interaction, the electronic, optical and magnetic properties of Mn-doped ZnSe nanocrystals as a function of magnetic fields and diameters are attained. The magnetic field splits the spin-degenerate states because of the sp-d exchange interaction. The minor reduction of optical band gaps is realized with the increasing magnetic fields. The optical band gaps are significantly decreased with the increasing diameters due to the quantum confinement effect. With the increasing magnetic fields, Zeeman splittings are improved but g-factor values are reduced. The g-factor values are promoted with the increasing diameters. The calculated Zeeman splitting and exciton g-factor value reveal a good agreement with the experimental records. The magnetic field divides the optical spectra into two σ+ and σ− circularly polarized components. Overall, this study will assist the fundamental understanding of the magnetically-doped semiconductor nanocrystals which is valuable for spintronic applications.