Two mini-band model for self-sustained oscillations of the current through resonant tunneling semiconductor superlattices

Abstract

A two miniband model for electron transport in semiconductor superlattices that includes scattering and interminiband tunnelling is proposed. The model is formulated in terms of Wigner functions in a basis spanned by Pauli matrices, includes electron-electron scattering in the Hartree approximation and modified Bhatnagar-Gross-Krook collision tems. For strong applied fields, balance equations for the electric field and the miniband populations are derived using a Chapman-Enskog perturbation technique. These equations are then solved numerically for a dc voltage biased superlattice. Results include self-sustained current oscillations due to repeated nucleation of electric field pulses at the injecting contact region and their motion towards the collector. Numerical reconstruction of the Wigner functions shows that the miniband with higher energy is empty during most of the oscillation period: it becomes populated only when the local electric field (corresponding to the passing pulse) is sufficiently large to trigger resonant tunneling.

26 pages, 3 figures, to appear in Phys. Rev. B

References in corpus (6)

• Electrically tunable GHz oscillations in doped GaAs-AlAs superlattices
• A multiband envelope function model for quantum transport in a tunneling diode
• Generalized drift-diffusion model for miniband superlattices
• Multi-band Wigner Function Formulation of Quantum Transport
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Cited by in corpus (4)

• Wigner-function formalism applied to semiconductor quantum devices: Need for nonlocal scattering models
• A novel exact solution to transmission problem of electron wave in a nonlinear Kronig-Penney superlattice
• Nonequilibrium free energy, H theorem and self-sustained oscillations for Boltzmann-BGK descriptions of semiconductor superlattices
• Charge transport in a superlattice: a numerical study using moment methods