Spin-dependent exciton-exciton interaction in quantum wells under an electric field

We give conclusive experimental evidence that spin-dependent exciton-excito n interaction processes can be altered by directly modifying the spatial ex citon structure applying an electric field. The previously observed energy splitting in spin-polarized, dense exciton gases can be varied by the elect ric field from a maximum of 4 meV to 0 meV. On the basis of an earlier deve loped theoretical model it is seen that inter-exciton scattering processes dominating at zero field are quenched and others are enhanced on increasing the field strength.