Two Miniband Model for Self-Sustained Oscillations of the Current through Resonant-Tunneling Semiconductor Superlattices Articles uri icon

publication date

  • July 2010

start page

  • 35305

issue

  • 3

volume

  • 82

international standard serial number (ISSN)

  • 1098-0121

electronic international standard serial number (EISSN)

  • 1538-4489

abstract

  • A two miniband model for electron transport in semiconductor superlattices that includes scattering and interminiband tunnelling is proposed. The model equations for Wigner functions in a basis spanned by
    Pauli matrices include electron-electron scattering in the Hartree
    approximation and modified Bhatnagar-Gross-Krook collision terms. 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 toward 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.