Anomalous giant Rashba spin splitting in two-dimensional hole systems

Rashba spin splitting in quasi two-dimensional systems originates from the inversion asymmetry of the confining potential usually quantified in terms of an electric field. We demonstrate both theoretically and experimentally, that in 2D heavy hole systems in accumulation layer-like single heterostructures, a decreasing, but nonzero electric field results in an increasing Rashba coefficient.