The dynamical density-response function of a periodically modulated two-dimensional electron gas under a perpendicular magnetic field is calculated within the random-phase approximation. It is found that the response function is not only broadened by the periodic potential, it also contains a series of subsingularities at the band edges. The maximum number of subsingularities is 2nmax, where nmax is the number of occupied Landau leveles (the last level may be partially filled). It is further proposed that light-scattering or electromagnetic absorption experiments can be performed to study these predicted structures.
History
Citation
This article was originally published as: Stewart, SM & Zhang, C, Response function of a two-dimensional electron gas in a unidirectional periodic potential, Physical Review B, 1995, R17036-R17039. Copyright 1995 American Physical Society. The original journal can be found here.