Density-of-states of a two-dimensional electron gas in multiple quantum well structures due to electron-phonon interaction

Abstract

Abstract Density-of-states (DOS) of a quasi-two-dimensional electron gas subjected to a high magnetic field applied perpendicularly to the electronic layer as formed in multiple quantum well structures (MQWS) is calculated. The second moment (σ0) representing the broadening of the Gaussian density-of-states of the ground Landau level due to the electron-acoustic and electron-piezoelectric phonon interaction is theoretically and numerically computed for the MQWS in GaAs/AlAs. The contribution of the acoustic phonon scattering is found to be larger than that due to the electron-piezoelectric phonon interaction, however piezoelectric phonon scattering is significant in MQWS. Magnetic field (B) dependence of σ0 due to the acoustic and piezoelectric scattering is given approximately as B 1 2 and B 1 4 respectively. Obtained numerical values of σ0 indicate that at low temperatures the combined effect of an acoustic and piezoelectric phonon scattering is of considerable and competing importance as that of the impurity scattering effects in MQWS.