Electronic states and collective excitations of a two-dimensional electron gas in a unidirectional magnetic-field modulation

We study a two-dimensional (2D) electron gas in the presence of a spatially modulated magnetic field. It is found that the 2D electron gas displays a trend of forming an array of 1D-like structures as the amplitude or spatial period of the modulation field increases. This is most evidently seen in the electron-density distribution of the system. The self-consistent potential, which arises from the modulation-induced nonuniform electron-density distribution, is included in the calculation, and found to weaken this 2D-to-1D-like transition, in competition with the magnetic-field modulation. The collective excitation spectra are calculated in this regime for different system parameters.