Magnetic exciton in a two-layer system

The bound state of a light electron of mass m(e) and a heavy hole of mass m(h) (m(h)>>m(e)) is considered for a two-layer system in a magnetic field. The field is assumed strong only for the electron (a(B)(e)>>l(0), where a(B)(e)=(h) over bar(2)/(m(e)e(2)) is the Bohr radius, and l(0)=root c (h) over bar/(eB) is the magnetic length). A new method of calculation is proposed by which one can find the ground-state energy of a magnetic exciton and the spectrum of its excited states without assuming that the Coulomb interaction is small. The effective mass m* is found, and the dependence of the energy of the exciton on its momentum P is obtained. The behavior of the exciton in crossed electric and magnetic fields is investigated. The results can be used for analysis of experiments in real magnetic fields similar to 10(4)-10(5) Oe for such semiconductors as InSb, InAs, GaAs, etc., where the ratio m(e)/m(h)less than or similar to 0.1. (C) 2000 American Institute of Physics. [S1063-777X(00)00608-3].