title: Characterization of spin-orbit interactions of GaAs heavy holes using a quantum point contact.
abstract: We present transport experiments performed in high-quality quantum point contacts embedded in a GaAs two-dimensional hole gas. The strong spin-orbit interaction results in peculiar transport phenomena, including the previously observed anisotropic Zeeman splitting and level-dependent effective g factors. Here we find additional effects, namely, the crossing and the anticrossing of spin-split levels depending on subband index and magnetic field direction. Our experimental observations are reconciled in a heavy-hole effective spin-orbit Hamiltonian where cubic- and quadratic-in-momentum terms appear. The spin-orbit components, being of great importance for quantum computing applications, are characterized in terms of magnitude and spin structure. In light of our results, we explain the level-dependent effective g factor in an in-plane field. Through a tilted magnetic field analysis, we show that the quantum point contact out-of-plane g factor saturates around the predicted 7.2 bulk value.
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Nichele
authors.affiliation: CEMS, RIKEN, Wako, Saitama 351-0198, Japan and Beijing Computational Science Research Center, Beijing 100084, China.
authors.forename: Stefano
authors.initials: S
authors.lastname: Chesi
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Szymon
authors.initials: S
authors.lastname: Hennel
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Angela
authors.initials: A
authors.lastname: Wittmann
authors.affiliation: Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Gerl
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Werner
authors.initials: W
authors.lastname: Wegscheider
authors.affiliation: CEMS, RIKEN, Wako, Saitama 351-0198, Japan and Department of Physics, University of Basel, 4056 Basel, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Loss
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ihn
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Klaus
authors.initials: K
authors.lastname: Ensslin