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Altermagnets are a class of magnetic materials that exhibit unconventional transport properties, such as an anomalous Hall effect (AHE), despite having compensated sublattice magnetic moments. In this study, fundamental experimental evidence of the altermagnetic nature of hematite (α-FeO), is reported combining electrical transport with advanced X-ray photoemission electron microscopy (XPEEM) imaging with linear and circular dichroism contrast. These measurements directly visualize the Néel vector's coupling to the crystal orientation, confirming hematite's altermagnetic order and its symmetry-driven transport behavior. The transport measurements reveal an anisotropic AHE with a pronounced crystal orientation dependence, including a sign inversion for specific Néel vector alignments. Supported by first-principles theoretical calculations, how the interplay between collinear spin and crystal symmetry breaking drives the observed AHE is explained. These findings establish hematite as an altermagnet, paving the way for experimental identification of altermagnetic materials and their integration into spintronic technologies.
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http://dx.doi.org/10.1002/adma.202505019 | DOI Listing |
Nanoscale
September 2025
St. Petersburg State University, 199034 St. Petersburg, Russia.
Using angle-resolved photoemission spectroscopy (ARPES) with spin resolution, scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT) methods, we study the electronic structure of graphene-covered and bare Au/Co(0001) systems and reveal intriguing features, arising from the ferrimagnetic order in graphene and the underlying gold monolayer. In particular, a spin-polarized Dirac-cone-like state, intrinsically related to the induced magnetization of Au, was discovered at point. We have obtained a good agreement between experiment and theory for bare and graphene-covered Au/Co(0001) and have proven that both Au ferrimagnetism and the Dirac-cone-like band are intimately linked to the triangular loop dislocations present at the Au/Co interface.
View Article and Find Full Text PDFJ Elect Propuls
September 2025
Department of Aerospace Engineering, Universidad Carlos III de Madrid, Leganés, Spain.
The collisionless cross-field electron transport in an plasma configuration, representative of a Hall thruster, is studied using bispectral analysis on the data of a fully-kinetic simulation. The nonlinear, in-phase interaction of the oscillations of the azimuthal electric field and the electron density, both tied to the fundamental electron cyclotron drift instability (ECDI) mode, is found to be the main driver of electron transport. Higher-wavenumber ECDI modes do not drive anomalous transport directly; however, they are nonlinearly coupled with each other and with the fundamental ECDI mode.
View Article and Find Full Text PDFACS Nano
September 2025
Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
As a versatile platform for exploring exotic quantum phases, moiré superlattices, ranging from twisted graphene to twisted transition metal dichalcogenides, have been intensively studied. In this work, based on exact diagonalization and Hartree-Fock mean-field calculations, the interaction-driven topological phases are investigated in hole-doped twisted bilayer MoS at the high filling factor = 3. Besides the nematic insulator and quantum anomalous Hall phases, the topological Wigner molecule crystal (TWMC) phase is found in the phase diagram.
View Article and Find Full Text PDFACS Nano
September 2025
Ultrafast Electron Microscopy Laboratory, The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin 300071, China.
Superlattices (SLs) based on two-dimensional (2D) van der Waals (vdW) materials, abbreviated as 2D-SLs, have garnered significant attention due to their customizable properties. 2D-SLs can be engineered by mechanical stacking or chemical intercalation to achieve diverse forms of symmetry breaking, resulting in exotic phenomena like the quantum anomalous Hall effect and topological magnetism. Hitherto, broken symmetries in 2D-SLs have been widely produced within lateral planes or three dimensions.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
School of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
The interplay between topology and magnetism induces various exotic quantum phenomena, with magnetic topological insulators (MTIs) serving as a prominent example due to their ability to host the quantum anomalous Hall effect (QAHE). However, the realization of the QAHE at a higher temperature approaching the magnetic transition temperature remains a significant challenge, primarily due to the scarcity of suitable material platforms and our limited understanding of the intricate relationships among band topology, magnetism, and defects. Here, we report a comprehensive investigation of MnSbTe·(SbTe) ( = 0-5) single crystals, including the discovery of the novel MnSbTe pure phase.
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