Topological materials may exhibit Hall-like currents flowing transversely to the applied electric field even in the absence of a magnetic field. In graphene superlattices, which have broken inversion symmetry, topological currents originating from graphene's two valleys are predicted to flow in opposite directions and combine to produce long-range charge neutral flow. We observed this effect as a nonlocal voltage at zero magnetic field in a narrow energy range near Dirac points at distances as large as several micrometers away from the nominal current path. Locally, topological currents are comparable in strength with the applied current, indicating large valley-Hall angles. The long-range character of topological currents and their transistor-like control by means of gate voltage can be exploited for information processing based on valley degrees of freedom.
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http://dx.doi.org/10.1126/science.1254966 | DOI Listing |
Sci Adv
January 2025
Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Introducing superconductivity in topological materials can lead to innovative electronic phases and device functionalities. Here, we present a unique strategy for quantum engineering of superconducting junctions in moiré materials through direct, on-chip, and fully encapsulated 2D crystal growth. We achieve robust and designable superconductivity in Pd-metalized twisted bilayer molybdenum ditelluride (MoTe) and observe anomalous superconducting effects in high-quality junctions across ~20 moiré cells.
View Article and Find Full Text PDFDynamic control of bound states in the continuum (BICs) is usually achieved by engineering structural geometries of lossless optical systems, leading to a passive nature for most current BIC devices. Introducing materials with tunable permittivity, i.e.
View Article and Find Full Text PDFIn confluent cell monolayers, patterns of cell forces and motion are systematically altered near topological defects in cell shape. In turn, defects have been proposed to alter cell density, extrusion, and invasion, but it remains unclear how the defects form and how they affect cell forces and motion. Here, we studied +1/2 defects, and, in contrast to prior studies, we observed both tail-to-head and head-to-tail defect motion occurring at the same time in the same cell monolayer.
View Article and Find Full Text PDFBMC Chem
January 2025
Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
The structural and electronic behavior of thiosemicarbazone (TSC)-based metal complexes of Mn (II), Fe (II), and Ni (II) have been investigated. The synthesized metal complexes were characterized using elemental analysis, magnetic susceptibility, molar conductivity, FTIR, and UV-Vis spectroscopy, the computational path helped with further structural investigation. The solubility test on the TSC and its complexes revealed their solubility in most organic solvents.
View Article and Find Full Text PDFCurr Biol
January 2025
Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
Dinosaurs dominated Mesozoic terrestrial ecosystems for ∼160 million years, but their biogeographic origin remains poorly understood. The earliest unequivocal dinosaur fossils appear in the Carnian (∼230 Ma) of southern South America and Africa, leading most authors to propose southwestern Gondwana as the likely center of origin. However, the high taxonomic and morphological diversity of these earliest assemblages suggests a more ancient evolutionary history that is currently unsampled.
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