Modulation of Fano resonances by an external magnetic field in semiconductor quantum wells

We have studied the dimensionality dependence of the behavior of Fano resonances in the photoluminescence excitation spectra of GaAs---AlxGa1−xAs heterostructures in a magnetic field applied in the Faraday configuration. A striking difference is observed between quasi-two and quasi-three-dimensional systems: while the Fano profiles evolve into Lorentzian lineshapes in two-dimensional systems, Fano resonances emerge from the continuum in three-dimensional-systems with increasing magnetic field.