We study the Landau levels in curved graphene sheets by measuring the discrete energy spectrum in the presence of a magnetic field. We observe that in rippled graphene sheets, the Landau energy levels satisfy the same square root dependence on the energy quantum number as in flat sheets, [Formula: see text]. Though, we find that the Landau levels in curved sheets are shifted towards lower energies by an amount proportional to the average spatial deformation of the sheet. Our findings are relevant for the quantum Hall effect in curved graphene sheets, which is directly related to Landau quantization. For the purpose of this study, we develop a new numerical method, based on the quantum lattice Boltzmann method, to solve the Dirac equation on curved manifolds, describing the low-energetic states in strained graphene sheets.
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http://dx.doi.org/10.1088/1361-648X/aadecd | DOI Listing |
ACS Macro Lett
January 2025
Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea.
As three-dimensional (3D) printing has emerged as a new manufacturing technology, the demand for high-performance 3D printable materials has increased to ensure broad applicability in various load-bearing structures. In particular, the thixotropic properties of materials, which allow them to flow under applied external forces but resist flowing otherwise, have been reported to enable rapid and high-resolution printing owing to their self-standing and easily processable characteristics. In this context, graphene nanosheets exhibit unique π-π stacking interactions between neighboring sheets, likely imparting self-standing capability to low-viscosity inks.
View Article and Find Full Text PDFSci Rep
January 2025
Preparatory Institute for Engineering Studies of Kairouan, (I.P.E.I.K) University of Kairouan, Kairouan, Tunisia.
We present a comprehensive analysis of the optical attributes of graphene sheets with charge carriers residing on a curved substrate. In particular, we focus on the fascinating case of Beltrami geometry and provide an explicit parametrization for this curved two-dimensional surface. By employing the massless Dirac description that is characteristic of graphene, we investigate the impact of the curved geometry on the optical properties within the sample.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Shanghai Applied Radiation Institute, State Key Lab. Advanced Special Steel, Shanghai University, Shanghai 200444, China; Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008, China. Electronic address:
The clogging of sieving pores due to the complex sewage system of mixed molecules and nanoparticles of different scales is a difficulty in the membrane-based separation process. When the holes are reduced to the point where they can repel small molecules in the contaminants, large-molecule contaminants can adsorb to the holes and decrease the permeability. A similar question remains in new promising graphene oxide (GO) membranes.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Physics, Changwon National University, Changwon 51140, Republic of Korea.
A mechanically robust flexible transparent conductor with high thermal and chemical stability was fabricated from welded silver nanowire networks (w-Ag-NWs) sandwiched between multilayer graphene (MLG) and polyimide (PI) films. By modifying the gas flow dynamics and surface chemistry of the Cu surface during graphene growth, a highly crystalline and uniform MLG film was obtained on the Cu foil, which was then directly coated on the Ag-NW networks to serve as a barrier material. It was found that the highly crystalline layers in the MLG film compensate for structural defects, thus forming a perfect barrier film to shield Ag NWs from oxidation and sulfurization.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 61200 Brno, Czech Republic.
Phase contrast imaging is well-suited for studying weakly scattering samples. Its strength lies in its ability to measure how the phase of the electron beam is affected by the sample, even when other imaging techniques yield low contrast. In this study, we explore via simulations two phase contrast techniques: integrated center of mass (iCOM) and ptychography, specifically using the extended ptychographical iterative engine (ePIE).
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