Transition energies and magnetic properties of a neutral donor complex in a Gaussian GaAs quantum dot

•A D0 complex is studied in a GaAs quantum dot with Gaussian confinement in a magnetic field.•The binding energy (BE) and 1s→2p−1s→2p− transition energy are obtained variationally.•As the dot size is reduced, BE initially increases, attains a maximum and then decreases.•The transition energy decreases with increasing magnetic field and the depth of the Gaussian potential.•The susceptibility of the D0 complex turns out to be diamagnetic.

The problem of a neutral hydrogenic donor (D0) centre located at the centre of a GaAs quantum dot with Gaussian confinement is studied in the presence of an external magnetic field. The ground and the first excited state energies and the corresponding binding energies are obtained as functions of the potential strength, quantum dot radius and the magnetic field using a variational method. It is suggested that the first excited state of the D0 centre is bound for sufficiently strong confinement potential. The 1s−2p−1s−2p− transition energy and the magnetic susceptibilities for the ground and the first excited states are also determined.