Quantum-beat recombination echoes

A recombination echo phenomenon of weakly coupled electron-hole pairs in di sordered semiconductors is suggested. The time-domain calculation of spin-d ependent recombination within such pairs indicates that dephasing beat osci llations can take place in a magnetic field and a phase recovery due to a r esonant microwave pulse is possible. This effect, which we call the quantum -beat recombination echo, is illustrated for different pulse sequences. App lications for material characterisation and quantum computing are suggested .