Observation of high Rydberg states of one-dimensional excitons in GaAs quantum wires by magnetophotoluminescence excitation spectroscopy

We have studied the higher Rydberg states of the ground exciton in T-shaped GaAs quantum wires with low-temperature photoluminescence excitation spectroscopy under magnetic fields. The peak of the second even-parity Rydberg state appears and grows in intensity at the onset of the one-dimensional (1D) continuum edge under strong magnetic fields. In stark contrast to the ground exciton, it shows significantly low zero-field oscillator strength and a large diamagnetic shift. These characteristic features are attributed to the extremely weakly bound wave function of the second Rydberg state, reflecting the inherent and novel character of 1D excitons that was predicted theoretically.