Collective excitations of a two-dimensional electron gas in a two-dimensional magnetic-field modulation

Abstract

We study the collective excitations of a two-dimensional electron gas in the presence of a spatially periodic magnetic field. Both frequency and oscillator strength of the excitations are calculated, and their dependences on the wave vector and magnetic-field strength are investigated. We focus on the regime where the uniform and modulation components of the field have the same strength, and the magnetic flux per unit cell is a few times the fundamental quantum flux hc/e. The possibility of observing the Hofstadter-type spectrum is discussed.