The reconstructed moiré superlattices of the transition metal chalcogenide (TMD), formed by the combined effects of interlayer coupling and intralayer strain, provide a platform for exploring quantum physics. Here, using scanning tunneling microscopy/spectroscopy, we observe that the strained WSe/WS moiré superlattices undergo various out-of-plane atomically buckled configurations, a phenomenon termed out-of-plane reconstruction. This evolution is attributed to the differentiated response of intralayer strain in high-symmetry stacking regions to external strain. Notably, in larger out-of-plane reconstructions, there is a significant alteration in the local density of states (LDOS) near the Γ point in the valence band, exceeding 300%, with the moiré potential in the valence band surpassing 200 meV. Further, we confirm that the variation in interlayer coupling within high-symmetry stacking regions is the main factor affecting the moiré electronic states rather than the intralayer strain. Our study unveils intrinsic regulating mechanisms of out-of-plane reconstructed moiré superlattices and contributes to the study of reconstructed moiré physics.
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http://dx.doi.org/10.1021/acsnano.4c08081 | DOI Listing |
Nano Lett
January 2025
Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027 Zhejiang, China.
Chiral vortices and their phase transition in ferroelectric/dielectric heterostructures have drawn significant attention in the field of condensed matter. However, the dynamical origin of the chiral phase transition from achiral to chiral polar vortices has remained elusive. Here, we develop a phase-field perturbation model and discover the softening of out-of-plane vibration mode of polar vortices in [(PbTiO)/(SrTiO)] superlattices at a critical epitaxial strain or temperature.
View Article and Find Full Text PDFACS Nano
January 2025
IBM Research Europe─Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
Highly ordered nanocrystal (NC) assemblies, namely, superlattices (SLs), have been investigated as materials for optical and optoelectronic devices due to their unique properties based on interactions among neighboring NCs. In particular, lead halide perovskite NC SLs have attracted significant attention owing to their extraordinary optical characteristics of individual NCs and collective emission processes like superfluorescence (SF). So far, the primary method for preparing perovskite NC SLs has been the drying-mediated self-assembly method, in which the colloidal NCs spontaneously assemble into SLs during solvent evaporation.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
College of Materials and Textile Engineering, Jiaxing University, Jiaxing 314001, China.
Programmable organization of uniform organic/inorganic functional building blocks into large-scale ordered superlattices has attracted considerable attention since the bottom-up self-organization strategy opens up a robust and universal route for designing novel and multifunctional materials with advanced applications in memory storage devices, catalysis, photonic crystals, and biotherapy. Despite making great efforts in the construction of superlattice materials, there still remains a challenge in the preparation of organic/inorganic hybrid superlattices with tunable dimensions and exotic configurations. Here, we report the spontaneous self-organization of polystyrene-tethered gold nanoparticles (AuNPs@PS) into freestanding organic/inorganic hybrid superlattices templated at the diethylene glycol-air interface.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, P.R. China.
Heat dissipation has become a critical challenge in modern electronics, driving the need for a revolution in thermal management strategies beyond traditional packaging materials, thermal interface materials, and heat sinks. Cubic boron arsenide (c-BAs) offers a promising solution, thanks to its combination of high thermal conductivity and high ambipolar mobility, making it highly suitable for applications in both electronic devices and thermal management. However, challenges remain, particularly in the large-scale synthesis of a high-quality material and the tuning of its physical properties.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Faculty of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan.
To realize the optical transfer of electron spin information, developing a semiconductor layer for efficient transport of spin-polarized electrons to the active layers is necessary. In this study, electron spin transport from a GaAs/AlGaAs superlattice (SL) barrier to InGaAs quantum dots (QDs) is investigated at room temperature through a combination of time-resolved photoluminescence and rate equation analysis, separating the two transport processes from the GaAs layer around the QDs and SL barrier. The electron transport time in the SL increases for a thicker quantum well (QW) of SL due to the weaker wavefunction overlap between adjacent QWs.
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