The Embedded Electron-Gas Boundary: A New Standard Problem in Surface Physics
Technical rept. no. 36, 1 Jan-31 Dec 91,
CALIFORNIA UNIV SANTA BARBARA DEPT OF PHYSICS
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Consider a nonneutral system consisting of a broad but finite slab of immobile uniform positive charge interpenetrated by mobile interacting electrons of total charge less than that of the positive background. This idealised configuration, which is termed an embedded electron gas, is approximated by the wide parabolic quantum wells now being grown by molecular beam epitaxy in the GaAsGaAlAs system. Compared with the electron density profile of the standard Lang-Kohn jellium edge, the boundary of the embedded electron gas is sharper as a result of the continuation of the jellium background outside the electron gas. This is expected to cause significant differences between the surface properties of the embedded electron gas and those of the regular jellium surface model long used to study the surface properties of simple metals. Since the readily excited centre-of-mass motions of the parabolic-well electronic density are now known to be insensitive to subband and many-body effects, surface properties such as those considered here may take on increased significance for the study of many body phenomena in such systems.
- Solid State Physics