Spin-resonant splitting in magnetically modulated semimagnetic semiconductor superlattices

We investigate spin-resonant splitting in magnetically modulated semimagnetic semiconductor superlattices by adopting tight-binding model and Green's function method under the influence of an external electric field. Spin-dependent resonant splitting features for both the transmission spectra and the current density spectra are discussed in more detail. Under no influence of the external electric field, the periodic nature of the spin superlattice leads to a regular profile of quantization in the transmission, which is composed of spin-dependent resonant bands separated by nonresonant gaps, where the resonant splitting rule of the transmission for spin-up case is exactly the same as that for spin-down case. The transmission resonances are drastically suppressed by the external electric field, the difference between resonant bands and nonresonant gaps is lessened and the transmission spectra are smoothed out. It is shown that splitting of the current density is more complex. In contrast with the transmission, the number of oscillations in the current density spectra has no simple direct correspondence to the number of unit cells and cannot be summarized in the simple rule.