Exciton binding energy in a quantum wire in the presence of a magnetic field

Abstract
A calculation of the ground-state energy of an exciton confined in a cylindrical quantum wire in the presence of a uniform magnetic field is reported as a function of wire radius, using a variational approach. It is assumed that the magnetic field is applied parallel to the axis of the wire. The calculations have been performed using a suitable variational wave function taken as a product of the appropriate confining confluent hypergeometric functions and a hydrogenic function for infinite and finite confining potentials. For a given value of the magnetic field, the binding energy is found to be larger than the zero-field case. This behavior is explained in terms of an average electron-hole separation, which depends on the wire radius, and the magnetic-field strength.