Magnetic frustrations in two-dimensional materials provide a rich playground to engineer unconventional phenomena. However, despite intense efforts, a realization of tunable frustrated magnetic order in two-dimensional materials remains an open challenge. Here we propose Coulomb engineering as a versatile strategy to tailor magnetic ground states in layered materials. Using the frustrated van der Waals monolayer 1T-TaSas an example, we show how long-range Coulomb interactions renormalize the low energy nearly flat band structure, leading to a Heisenberg model which depends on the Coulomb interactions. Based on this, we show that superexchange couplings in the material can be precisely tailored by means of environmental dielectric screening, ultimately allowing to externally drive the material towards a tunable frustrated regime. Our results put forward Coulomb engineering as a powerful tool to manipulate magnetic properties of van der Waals materials.
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http://dx.doi.org/10.1088/1361-648X/ac9812 | DOI Listing |
ACS Nano
January 2025
Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
With the potential to surpass the Shockley-Queisser (S-Q) limitation for solar energy conversion, the bulk photovoltaic (BPV) effect, which is induced by the broken inversion symmetry of the lattice, presents prospects for future light-harvesting technologies. However, the development of BPV is largely limited by the low solar spectrum conversion efficiency of existing noncentrosymmetric materials with wide band gaps. This study reports that the strain-induced reduction of inversion symmetry can enhance the second-order nonlinear susceptibility (χ) of SnPSe crystals by an order of magnitude, which contributes to an extremely high value of 1.
View Article and Find Full Text PDFNat Chem
January 2025
Laboratory of Advanced Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Chemistry for Energy Materials (2011-iChEM), College of Chemistry and Materials, Fudan University, Shanghai, P. R. China.
The synthesis of mesoporous metal-organic frameworks (meso-MOFs) is desirable as these materials can be used in various applications. However, owing to the imbalance in structural tension at the micro-scale (MOF crystallization) and the meso-scales (assembly of micelles with MOF subunits), the formation of single-crystal meso-MOFs is challenging. Here we report the preparation of uniform single-crystal meso-MOF nanoparticles with ordered mesopore channels in microporous frameworks with definite arrangements, through a cooperative assembly method co-mediated by strong and weak acids.
View Article and Find Full Text PDFACS Nano
January 2025
Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany.
The reduced dimensionality of thin transition metal dihalide films on single-crystal surfaces unlocks a diverse range of magnetic and electronic properties. However, achieving stoichiometric monolayer islands requires precise control over the growth conditions. In this study, we employ scanning probe microscopy to investigate the growth of MnI on Ag(111) via single-crucible evaporation.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Institute of Nano Science and Technology, Sector 81, Knowledge City, Manauli, Mohali, Mohali, Punjab, 140306, INDIA.
Two-dimensional (2D) materials hold great promise for the next-generation optoelectronics applications, many of which, including solar cell, rely on the efficient dissociation of exciton into free charge carriers. However, photoexcitation in atomically thin 2D semiconductors typically produces exciton with a binding energy of ~500 meV, an order of magnitude larger than thermal energy at room temperature. This inefficient exciton dissociation can limit the efficiency of photovoltaics.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Northeastern University, College of Science, Northeastern University, Shenyang 110819, China, Shenyang, Liaoning, 110819, CHINA.
Based on the recent discovery of intrinsic magnetism in monolayer films VSe2, we have constructed a two-dimensional (2D) Heisenberg model incorporating the 1T and 2H structures. These configurations consist of three layers: the upper and lower surface layers and a middle layer. Using the retarded Green's function method, we investigate the spin-wave energy spectrum, spin-wave density of states, and transition temperature of the system.
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