When the backscattering of the host crystal is appropriately matched to the scattering of a point defect, a resonance in the induced density of states will occur. We show that this crystal backscattering resonance, which can occur even when the defect scattering is weak, is allowed only where the host density of states is small. The giant enhancement of the muon Knight shift in antimony is interpreted in terms of this resonance. The same mechanism provides an interpretation within scattering theory for the formation of bound states at point defects.

• Received 2 January 1985

DOI:https://doi.org/10.1103/PhysRevB.31.6273