Topological materials have become promising materials for next-generation devices by utilizing their exotic electronic states. Their exotic states caused by spin-orbital coupling usually locate on the surfaces or at the edges. Scanning tunneling spectroscopy (STS) is a powerful tool to reveal the local electronic structures of condensed matters. Therefore, STS provides us with an almost perfect method to access the exotic states of topological materials. In this topical review, we report the current investigations by several methods based on the STS technique for layered topological material from transition metal dichalcogenide Weyl semimetals (WTe and MoTe) to two dimensional topological insulators (layered bismuth and silicene). The electronic characteristics of these layered topological materials are experimentally identified.
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http://dx.doi.org/10.1088/1361-648X/ab777d | DOI Listing |
Nat Mater
January 2025
Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA.
Spin waves, or magnons, are essential for next-generation energy-efficient spintronics and magnonics. Yet, visualizing spin-wave dynamics at nanoscale and microwave frequencies remains a formidable challenge due to the lack of spin-sensitive, time-resolved microscopy. Here we report a breakthrough in imaging dipole-exchange spin waves in a ferromagnetic film owing to the development of laser-free ultrafast Lorentz electron microscopy, which is equipped with a microwave-mediated electron pulser for high spatiotemporal resolution.
View Article and Find Full Text PDFSci Bull (Beijing)
January 2025
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea; Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea; Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea; POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang 37673, Republic of Korea. Electronic address:
Band topology has emerged as a novel tool for material design across various domains, including photonic and phononic systems, and metamaterials. A prominent model for band topology is the Su-Schrieffer-Heeger (SSH) chain, which reveals topological in-gap states within Bragg-type gaps (BG) formed by periodic modification. Apart from classical BGs, another mechanism for bandgap formation in metamaterials involves strong coupling between local resonances and propagating waves, resulting in a local resonance-induced bandgap (LRG).
View Article and Find Full Text PDFJ Mol Model
January 2025
PG & Research Department of Mathematics, Sanatana Dharma College, Kerala University, Alappuzha, Kerala, 688003, India.
Holey nanographene, an allotrope of carbon arranged in two dimensions, has gained remarkable attention as a nanomaterial with several potential uses in numerous industries, such as electronics, energy storage, healthcare, and environmental cleanup, because of its high carrier mobility, flexibility, transparency, high surface area, conductivity, and chemical stability. The fundamental holey nanographene is assembled in a linear form to create the holey nanographene chain (HNC) that is being discussed. To fully utilize it in various applications, it is essential to comprehend the basic ideas guiding its behavior at the nanoscale; for that, we find various topological indices for this holey nanographene chain using the cut method.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086 Tallinn, Estonia.
Interpenetrating phase composites are a novel class of heterogeneous structures that have recently gained attention. In these types of composites, one of the phases is topologically continuous and can maintain its structural integrity even if the other phase is removed. These composites are generally fabricated by casting, where the reinforcement penetrates into the precursor matrix as a continuous phase.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Tsinghua University, Beijing 10084, China.
Actinide elements are characterized by their unique electronic correlations, variable valence states, and localized 5f electrons, leading to unconventional electronic and topological properties in their compounds. The distinctive physical properties of actinide materials are maintained in low-dimensional forms, yet two-dimensional (2D) actinide materials remain largely unexplored due to their scarcity and the experimental challenges posed by their radioactivity. To fill the knowledge gap in 2D actinide materials, we theoretically designed a series of stable thorium-containing 2D materials, including MXenes, chalcogenides, halides, and other compounds with unique structures.
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