The orbital Hall effect refers to the generation of electron orbital angular momentum flow transverse to an external electric field. Contrary to the common belief that the orbital angular momentum is quenched in solids, theoretical studies predict that the orbital Hall effect can be strong and is a fundamental origin of the spin Hall effect in many transition metals. Despite the growing circumstantial evidence, its direct detection remains elusive. Here we report the magneto-optical observation of the orbital Hall effect in the light metal titanium (Ti). The Kerr rotation by the orbital magnetic moment accumulated at Ti surfaces owing to the orbital Hall current is measured, and the result agrees with theoretical calculations semi-quantitatively and is supported by the orbital torque measurement in Ti-based magnetic heterostructures. This result confirms the orbital Hall effect and indicates that the orbital angular momentum is an important dynamic degree of freedom in solids. Moreover, this calls for renewed studies of the orbital effect on other degrees of freedom such as spin, valley, phonon and magnon dynamics.
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http://dx.doi.org/10.1038/s41586-023-06101-9 | DOI Listing |
J Phys Condens Matter
December 2024
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.
View Article and Find Full Text PDFUsing 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.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Mathematics and Statistics, Manipal University Jaipur, Jaipur, 303007, Rajasthan, India.
This article discusses a finite-source stock-dependent stochastic inventory system with multiple servers and a retrial facility. The system can store a maximum of S items, and the lifetime of each item is exponentially distributed. The primary customer arrives at the waiting hall from the finite source and receives service from multi-servers.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan.
For over a century, the Hall effect, a transverse effect under an out-of-plane magnetic field or magnetization, has been a cornerstone for magnetotransport studies and applications. Modern theoretical formulation based on the Berry curvature has revealed the potential that even an in-plane magnetic field can induce an anomalous Hall effect, but its experimental demonstration has remained difficult due to its potentially small magnitude and strict symmetry requirements. Here, we report observation of the in-plane anomalous Hall effect by measuring low-carrier density films of magnetic Weyl semimetal EuCd_{2}Sb_{2}.
View Article and Find Full Text PDFAdv Mater
December 2024
Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
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.
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