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Twisting bilayers of transition metal dichalcogenides gives rise to a moiré potential resulting in flat bands with localized wave functions and enhanced correlation effects. In this work, scanning tunneling microscopy is used to image a WS bilayer twisted approximately 3° off the antiparallel alignment. Scanning tunneling spectroscopy reveals localized states in the vicinity of the valence band onset, which is observed to occur first in regions with S-on-S Bernal stacking. In contrast, density functional theory calculations on twisted bilayers that have been relaxed in vacuum predict the highest-lying flat valence band to be localized in regions of AA' stacking. However, agreement with experiment is recovered when the calculations are performed on bilayers in which the atomic displacements from the unrelaxed positions have been reduced, reflecting the influence of the substrate and finite temperature. This demonstrates the delicate interplay of atomic relaxations and the electronic structure of twisted bilayer materials.
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http://dx.doi.org/10.1021/acs.nanolett.3c03735 | DOI Listing |
J Biomol NMR
September 2025
Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
Biomolecular dynamics in the microsecond-to-millisecond (µs-ms) timescale are linked to various biological functions, such as enzyme catalysis, allosteric regulation, and ligand recognition. In solution state NMR, Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments are commonly used to probe µs-ms timescale motions, providing detailed kinetic, thermodynamic, and mechanistic information at the atomic level. For investigating conformational dynamics in high-molecular-weight biomolecules, methyl groups serve as ideal probes due to their favorable relaxation properties, and C CPMG relaxation dispersion is widely employed for characterizing dynamics in selectively CH-labeled samples.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Masaryk University, Faculty of Science, Department of Chemistry, Kotlářská 2, Brno, 611 37, Czech Republic.
Structural and magnetic properties of ultra-small tetrahedron-shaped iron oxide nanoparticles were investigated using density functional theory. Tetrahedral and truncated tetrahedral models were considered in both non-functionalized form and with surfaces passivated by pseudo-hydrogen atoms. The focus on these two morphologies reflects their experimental relevance at this size scale and the feasibility of performing fully relaxed, atomistically resolved first-principles simulations.
View Article and Find Full Text PDFMagn Reson Lett
May 2025
Qingdao New Energy Shandong Laboratory, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
Nuclear magnetic resonance (NMR) serves as a powerful tool for studying both the structure and dynamics of proteins. The NOE method, alongside residual dipolar; coupling, paramagnetic effects, -coupling, and other related techniques, has reached a level of maturity that allows for the determination of protein structures. Furthermore, NMR relaxation methods prove to be highly effective in characterizing protein dynamics across various timescales.
View Article and Find Full Text PDFComput Biol Med
September 2025
Laboratorio de Procesado de Imagen (LPI), ETSI Telecomunicación, Universidad de Valladolid, Valladolid, Spain. Electronic address:
Modelling the diffusion-relaxation magnetic resonance (MR) signal obtained from multi-parametric sequences has recently gained immense interest in the community due to new techniques significantly reducing data acquisition time. A preferred approach for examining the diffusion-relaxation MR data is to follow the continuum modelling principle that employs kernels to represent the tissue features, such as the relaxations or diffusion properties. However, constructing reasonable dictionaries with predefined signal components depends on the sampling density of model parameter space, thus leading to a geometrical increase in the number of atoms per extra tissue parameter considered in the model.
View Article and Find Full Text PDFSci Adv
September 2025
National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Two-dimensional (2D) materials offer strong light-matter interaction and design flexibility beyond bulk semiconductors, but an intrinsic limit is the low absorption imposed by the atomic thickness. A long-sought-after goal is to achieve complementary absorption enhancement through energy transfer (ET) to break this limit. However, it is found challenging due to the competing charge transfer (CT) process and lack of resonance in exciton states.
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