Multidimensional Coherent Spectroscopy of Erbium Doped GaAs Quantum Wells

Rare-earth ions are appealing for a broad array of applications. When embedded in crystalline matrices, they combine well protected spin and optically active transitions which are useful to store and process quantum information. When doped in semiconductors, they have been intensely investigated as a new class of electrically active infrared-emitting materials. To better understand the interaction of rare-earth doping, we investigate the effect of dilute erbium doping in GaAs quantum wells. When doped into GaAs, the Er³⁺ ion substitutes Ga³⁺ forming ErAs, which is known to have “coupled” magnetic and electronic properties. As a magnetic material, there is a strong exchange coupling between the relatively large local moments of the 4f and valence and conduction electrons near the Fermi level. Using multidimensional coherent spectroscopy, we attempt to elucidate excited-state structure and interactions of the Er³⁺ doping in GaAs at different doping concentrations. This spectroscopy can characterize excited state dynamics and interactions.