Magnetoexcitons in two-dimensional electronic systems

Experimental and theoretical research on neutral excitations in a two-dimensional electron gas in a strong magnetic field is reviewed. Methods for calculating excitation energies in the strong-field limit for integer and noninteger filling factors are considered. The effects of impurities and of the nonideality of the two-dimensional system on the excitation spectrum are examined. Experimental results that have been obtained by the method of inelastic light scattering and that lend support to the current theoretical views are presented. We also discuss possible avenues of future experimental and theoretical work. (reviews of topical problems)