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Pramana

, Volume 52, Issue 1, pp 101–109 | Cite as

Plasmons and their damping in a doped semiconductor superlattice

  • P. Tripathi
  • A. C. Sharma
Article

Abstract

The complex zeroes of dielectric response function of a doped GaAs superlattice are computed to study the frequencies and damping rates of oscillations in coupled electron-hole plasma. The real part of a complex zero describes the plasma frequency, whereas imaginary part of it yields the damping rate. Strong scattering of charge carriers from random impurity potentials in a doped GaAs superlattice gives rise to a large value of damping rate which causes over-damping of plasma oscillations of coupled electron-hole gas below qc, a critical value of wave vector component (q) along the plane of a layer of electrons (holes). The plasma oscillations which correspond to electrons gas enter into over-damped regime for the case of weak coupling between layers. Whereas, plasma oscillations which belong to hole gas go to over-damped regime of oscillations for both strong as well as weak coupling between layers. The damping rate shows strongq-dependence forq < qc, whereas it weakly depends onq forqq c . The damping rate exhibits a sudden change atq =q c , indicating a transition from non-diffusive regime (where collective excitation can be excited) to diffusive regime (over-damped oscillations).

Keywords

Doping superlattice critical wave vector plasmons damping rate 

PACS Nos

73.20 68.65 

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Copyright information

© Indian Academy of Sciences 1999

Authors and Affiliations

  • P. Tripathi
    • 1
  • A. C. Sharma
    • 1
  1. 1.Physics Department, Faculty of ScienceM S University of BarodaVadodaraIndia

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