Incident-angle dependence of catastrophic dechanneling for strained-layer superlattices

A strong asymmetry has been observed in the angular dependence of the catastrophic dechanneling depth in strained-layer superlattices. This new effect occurs under resonance conditions, where the wavelength of the planar channeled particles equals the period of the superlattice, and is demonstrated for \{110\} planar channeling in GaP/GaAs_xP_1-x. A theoretical, phase-plane analysis shows that the angular tilt required for shifting of the catastrophic depth by one layer is a direct measure of the strain in the first few layers.