Band Structure of the Spin Excitations in Modulated Heterostructures Under Strong Magnetic Fields

Authors: T. Maniv, Yu.A. Bychkov, A. Kaplunovsky, and I.D. Vagner
Source: LaTex + 3 Figures in GIF format
Reference: Physica B 204, 1-4, 134-140 (1995)

The problem of single spin-excitons in a two-dimensional electron gas (2DEG) under a strong magnetic field, which is subject to artificially generated 1D periodic potentials with periods in the submicron range, is theoretically investigated. The corresponding spin-exciton band structure for parameters typical to the 2DEG in GaAs/Al_xGa_1-xAs heterostructure, is calculated. It is found that the periodic modulation potential can modify the single spin excitonic states so strongly, that their lowest energy is no longer the k=0 spin-exciton (which is uneffected by the periodic potential), but a finite k - state. The energy of this state approaches the zero excitation energy at a reasonably strong modulation potential. The corresponding many excitons problem and the possiblity of condensation of gapless excitons into a collective Spin Density Wave ground state is briefly discussed.

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