Plasmons and their damping in a doped semiconductor superlattice |
| |
Authors: | P Tripathi A C Sharma |
| |
Institution: | (1) Physics Department, Faculty of Science, M S University of Baroda, 390 002 Vadodara, India |
| |
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 forq ≥q
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 |
本文献已被 SpringerLink 等数据库收录! |
|