Anomalous spin-resolved point-contact transmission of holes due to cubic Rashba spin-orbit coupling

Stefano Chesi, Gabriele F. Giuliani, L. P. Rokhinson, L. N. Pfeiffer, K. W. West

Published 2010-11-11, updated 2011-06-11Version 2

Evidence is presented for the finite wave vector crossing of the two lowest one-dimensional spin-split subbands in quantum point contacts fabricated from two-dimensional hole gases with strong spin-orbit interaction. This phenomenon offers an elegant explanation for the anomalous sign of the spin polarization filtered by a point contact, as observed in magnetic focusing experiments. Anticrossing is introduced by a magnetic field parallel to the channel or an asymmetric potential transverse to it. Controlling the magnitude of the spin-splitting affords a novel mechanism for inverting the sign of the spin polarization.