scholarly journals Electromagnetic Absorption in Two-dimensional Systems under a Magnetic Field and a Unidirectional Periodic Potential

2000 ◽  
Vol 53 (1) ◽  
pp. 65
Author(s):  
C. Zhang
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Periodic Potential ◽  
Random Phase ◽  
Electron Gas ◽  
High Mobility ◽  
Impurity Scattering ◽  
Electron Interaction ◽  
Two Dimensional ◽  
Electromagnetic Absorption

The absorption of electromagnetic waves by a high mobility two-dimensional electron gas subjected to a magnetic field and a weak periodic potential is investigated. We show that the periodic modulation on the Laudau states has a profound effect on the absorption of electromagnetic waves. We develop a formalism which treats the electron–electron interaction beyond the random-phase-approximation (RPA) and includes the electron-impurity scattering in the lowest order. A RPA dielectric function was employed to study the electromagnetic absorption in modulated systems. Simultaneous excitation of an electron–hole pair with finite momentum contributes significantly to the absorption around and below the cyclotron frequency. Such a process is absent for a uniform electron gas under a magnetic field.

QUASIPARTICLE LIFETIME OF A TWO-DIMENSIONAL ELECTRON GAS

2010 ◽  
Vol 24 (09) ◽  
pp. 1103-1110
Author(s):  
A. ESMAILIAN ◽  
M. R. ABOLHASSANI
Keyword(s):  
Random Phase Approximation ◽  
Random Phase ◽  
Electron Gas ◽  
Electron Interaction ◽  
Two Dimensional ◽  
Effective Electron ◽  
2D Electron Gas ◽  
Small Correction ◽  
Electron Relaxation ◽  
Dimensional Electron Gas

We calculate the inelastic scattering lifetime of an excited quasiparticle at low (or zero) temperature, due to electron-electron interaction for a clean two-dimensional (2D) electron gas within the random-phase approximation (RPA) and compare it with the lifetime measured from the tunnelling experiment. Our result obtained by direct numerical calculation increases the electron relaxation rate considerably, hence decreases the size of discrepancy (roughly by a factor of 4) between theory and experiment which exists in the literature. We also show that including local-field factors in the effective electron interaction yields small correction to the result calculated within the RPA for rs ~ 1, corresponding to electron density of the sample in the tunnelling experiment. This result suggests that the RPA is reasonably accurate for a 2D electron gas in weak coupling limit.

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