Resonant hole states and multichannel scattering at quantum-well heterostructures

A numerical method was developed to calculate analytical continuation of S-matrix, which describes multichannel scattering at quantum wells, into the region of complex "nonphysical" energy values. One or several resonant hole states related to poles of S-matrix and to the absolute reflection at hole scattering on a quantum well were found to exist in the energy range where only heavy holes may propagate over barriers. Energies of resonant states (i.e. real parts of complex values of S-matrix poles) are close to those of peaks of absolute reflection. The qualitative behaviour of the over-barrier scattering and resonant states is the same at all material parameters and quantum well shapes, however lifetimes of resonant states depend strongly on all parameters. It appears that these resonant states account for the efficient hole capture by quantum wells.