The discovery of a new type of soliton occurring in periodic systems is reported. This type of nonlinear excitation exists at a Dirac point of a photonic band structure, and features an oscillating tail that damps algebraically. Solitons in periodic systems are localized states traditionally supported by photonic bandgaps. Here, it is found that besides photonic bandgaps, a Dirac point in the band structure of triangular optical lattices can also sustain solitons. Apart from their theoretical impact within the soliton theory, they have many potential uses because such solitons are possible in both Kerr material and photorefractive crystals that possess self-focusing and self-defocusing nonlinearities. The findings enrich the soliton family and provide information for studies of nonlinear waves in many branches of physics.
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http://dx.doi.org/10.1364/OE.25.030349 | DOI Listing |
Biosensors (Basel)
January 2025
Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda 386-8567, Nagano, Japan.
Nitrogen-based fertilizers are crucial in agriculture for maintaining soil health and increasing crop yields. Soil microorganisms transform nitrogen from fertilizers into NO3--N, which is absorbed by crops. However, some nitrogen is converted to nitrous oxide (NO), a greenhouse gas with a warming potential about 300-times greater than carbon dioxide (CO).
View Article and Find Full Text PDFQuantum materials governed by emergent topological fermions have become a cornerstone of physics. Dirac fermions in graphene form the basis for moiré quantum matter and Dirac fermions in magnetic topological insulators enabled the discovery of the quantum anomalous Hall (QAH) effect. By contrast, there are few materials whose electromagnetic response is dominated by emergent Weyl fermions.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Theoretical Science, Poornaprajna Institute of Scientific Research, Ranjith Kumar R, Department of Physics, Indian Institute of Technoloby Bombay, Mumbai, 400076, INDIA.
Understanding the critical properties is essential for determining the physical behavior of topological systems. In this context, scaling theories based on the curvature function in momentum space, the renormalization group (RG) method, and the universality of critical exponents have proven effective. In this work, we develop a scaling theory for non-Hermitian topological states of matter.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan.
Graphene-based supercapacitors have gained significant attention due to their exceptional energy storage capabilities. Despite numerous research efforts trying to improve the performance, the challenge of experimentally elucidating the nanoscale-interface molecular characteristics still needs to be tackled for device optimizations in commercial applications. To address this, we have conducted a series of experiments using substrate-free graphene field-effect transistors (SF-GFETs) and oxide-supported graphene field-effect transistors (OS-GFETs) to elucidate the graphene-electrolyte interfacial arrangement and corresponding capacitance under different surface potential states and ionic concentration environments.
View Article and Find Full Text PDFSci Rep
January 2025
Saint Petersburg State University, St. Petersburg, 198504, Russia.
Using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT), an experimental and theoretical study of changes in the electronic structure (dispersion dependencies) and corresponding modification of the energy band gap at the Dirac point (DP) for topological insulator (TI) [Formula: see text] have been carried out with gradual replacement of magnetic Mn atoms by non-magnetic Ge atoms when concentration of the latter was varied from 10% to 75%. It was shown that when Ge concentration increases, the bulk band gap decreases and reaches zero plateau in the concentration range of 45-60% while trivial surface states (TrSS) are present and exhibit an energy splitting of 100 and 70 meV in different types of measurements. It was also shown that TSS disappear from the measured band dispersions at a Ge concentration of about 40%.
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