Magnetostriction of an electron‐hole drop in Ge

By infrared imaging the shape of a strain‐confined electron‐hole drop in germanium is measured in an applied magnetic field, H ≦ 22 kOe. A considerable distortion from sphericity is observed for all field orientations and stress geometries studied. It is found that in most cases the drop flattens along the field direction. For II ‖〈111〉‖ (applied stress) the drop shape depends markedly on the position of the light excitation spot on the crystal. The dimension parallel to the field decays more rapidly than the perpendicular dimension. The data strongly support a dynamic interpretation in which the recombination currents of electrons and holes give rise to the field‐induced distortion.