Variation of Chemical Potential Oscillations of a 2DEG in a Quantum Well Under a Magnetic Field for Multiple Sub-Band Occupation as Function of Temperature and Level-Broadening

Authors: BERRİN ÖZDEMİR, ZEKİ YARAR, METİN ÖZDEMİR

Abstract: We study the variation of chemical potential in a two dimensional electron gas in a uniform magnetic field as a function of temperature and level-broadening parameter. Schrödinger and Poisson equations are solved self-consistently for a two dimensional electron gas formed in a Ga_xAl_{1-x}As/GaAs quantum well, to numerically determine the potential profile, empty or occupied energy sub-bands, the wavefunctions and electron concentrations corresponding to each sub-band at various temperatures. Then assuming that the electron concentration is not altered, the variation of chemical potential with respect to both temperature and energy level-broadening parameter is studied under a uniform and constant magnetic field. Gaussian, exponential and lorentzian forms of broadening are assumed and the results are compared. Increasing temperature or level-broadening have been found to have qualitatively the same effect on chemical potential oscillations, although the underlying processes are different. It is found that, as the number of occupied sub-bands increases, the shape of oscillations increases in complexity. The results can be directly tested by experimental studies.

Keywords: Chemical potential, level-broadening, quantum well, Poisson-Schrödinger solution

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