title: Enhanced spin-orbit coupling in core/shell nanowires.
abstract: The spin-orbit coupling (SOC) in semiconductors is strongly influenced by structural asymmetries, as prominently observed in bulk crystal structures that lack inversion symmetry. Here we study an additional effect on the SOC: the asymmetry induced by the large interface area between a nanowire core and its surrounding shell. Our experiments on purely wurtzite GaAs/AlGaAs core/shell nanowires demonstrate optical spin injection into a single free-standing nanowire and determine the effective electron g-factor of the hexagonal GaAs wurtzite phase. The spin relaxation is highly anisotropic in time-resolved micro-photoluminescence measurements on single nanowires, showing a significant increase of spin relaxation in external magnetic fields. This behaviour is counterintuitive compared with bulk wurtzite crystals. We present a model for the observed electron spin dynamics highlighting the dominant role of the interface-induced SOC in these core/shell nanowires. This enhanced SOC may represent an interesting tuning parameter for the implementation of spin-orbitronic concepts in semiconductor-based structures.
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Stephan
authors: S
authors: Furthmeier
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Florian
authors: F
authors: Dirnberger
authors: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Martin
authors: M
authors: Gmitra
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Andreas
authors: A
authors: Bayer
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Moritz
authors: M
authors: Forsch
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Joachim
authors: J
authors: Hubmann
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Christian
authors: C
authors: Schüller
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Elisabeth
authors: E
authors: Reiger
authors: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Jaroslav
authors: J
authors: Fabian
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Tobias
authors: T
authors: Korn
authors: Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors: Dominique
authors: D
authors: Bougeard