Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany.
Published: May 2013
AI Article Synopsis
Article Abstract
Using a generalized wave matching method we solve the full scattering problem for quantum spin Hall insulator-superconductor (SC)-quantum spin Hall insulator junctions. We find that for systems narrow enough so that the bulk states in the SC part couple both edges, the crossed Andreev reflection (CAR) is significant and the electron cotunneling (T) and CAR become spatially separated. We study the effectiveness of this separation as a function of the system geometry and the level of doping in the SC. Moreover, we show that the spatial separation of both effects allows for an all-electrical measurement of CAR and T separately in a five-terminal setup or by using the spin selection of the quantum spin Hall effect in an H-bar structure.
Department of Physics and Astronomy, University of Nebraska-Lincoln, Jorgenesen Hall, 855 North 16th Street, Lincoln, Nebraska, 68588-0299, UNITED STATES.
Evidence of chirality was observed at the Fe metal center in Fe(III) spin crossover coordination salts [Fe(qsal)Ni(dmit)] and [Fe(qsal)(TCNQ)] from X-ray absorption spectroscopy at the Fe 2pcore threshold. Based on the circularly polarized X-ray absorption data, the X-ray natural circular dichroism seen [Fe(qsal)Ni(dmit)] and [Fe(qsal)(TCNQ)] is far stronger than seen for [Fe(qsal)Cl] suggesting this natural circular dichroism signature is a ligand effect rather than a result of just a loss of octahedral symmetry on the Fe core. The larger the chiral effects in the Fe 2p core to bound X-ray absorption, the greater the perturbation of the Fe 2pto 2pspin-orbit splitting seen in the X-ray absorption spectra.
Using a full-wave theory to analyze the light beam scattering at sharp interfaces, we reexamine the anomalous spin-orbit interaction (SOI) around the Fresnel coefficient (FC) singularities. We evaluate the spin-dependent beam shifts near the singularity for three typical optical interfaces, comparing our results with existing ones. Existing theories neglect the contribution of the wave vector component near the FC singularities, potentially leading to erroneous results.
Ordered media often support vortex structures with intriguing topological properties. Here, we investigate non-Abelian vortices in tetrahedral order using the mathematical formalism of colored links. Due to the generality of our methods, the results apply to all physical systems governed by tetrahedral order, such as the cyclic phase of spin-2 Bose-Einstein condensates and the tetrahedratic phase of bent-core nematic liquid crystals.
The orbital Hall effect originating from light materials with weak spin-orbit coupling, has attracted considerable interest in spintronic applications. Recent studies demonstrate that orbital currents can be generated from charge currents through the orbital Hall effect in ferromagnetic materials. However, the generation of orbital currents in antiferromagnets has so far been elusive.
Antiferromagnetic materials have several unique properties, such as a vanishingly small net magnetization, which generates weak dipolar fields and makes them robust against perturbation from external magnetic fields and rapid magnetization dynamics, as dictated by the geometric mean of their exchange and anisotropy energies. However, experimental and theoretical techniques to detect and manipulate the antiferromagnetic order in a fully electrical manner must be developed to enable advanced spintronic devices with antiferromagnets as their active spin-dependent elements. Among the various antiferromagnetic materials, conducting antiferromagnets offer high electrical and thermal conductivities and strong electron-spin-phonon interactions.
