QUASI-ONE-DIMENSIONAL EXCITONS IN A QUANTUM-WIRE SUBJECTED TO A MAGNETIC-FIELD

We have calculated the binding energy and 'length' of a quasi one-dime nsional exciton in a semiconductor quantum wire subjected to a magneti c field. The magnetic field causes these quantities to have non-monoto nic dependences on wire width. Below a critical width, the binding ene rgy decreases with increasing wire width as usual, but above this crit ical width the opposite behavior is observed. This gives rise to a pro nounced minimum in the binding energy. A similar behavior gives rise t o a pronounced maximum in the exciton length. These features are expla ined by invoking the complementary roles of the electrostatic and magn etostatic confinement of the exciton. (C) 1996 Academic Press Limited