Monolayer transition metal dichalcogenides (TMDs) have a crystalline structure with broken spatial inversion symmetry, making them promising candidates for valleytronic applications. However, the degree of valley polarization is usually not high due to the presence of intervalley scattering. Here, we use the nanoindentation technique to fabricate strained structures of WSe on Au arrays, thus demonstrating the generation and detection of strained localized excitons in monolayer WSe. Enhanced emission of strain-localized excitons was observed as two sharp photoluminescence (PL) peaks measured using low-temperature PL spectroscopy. We attribute these emerging sharp peaks to excitons trapped in potential wells formed by local strains. Furthermore, the valley polarization of monolayer WSe is modulated by a magnetic field, and the valley polarization of strained localized excitons is increased, with a high value of up to approximately 79.6%. Our results show that tunable valley polarization and localized excitons can be realized in WSe monolayers, which may be useful for valleytronic applications.
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http://dx.doi.org/10.1364/OL.487201 | DOI Listing |
Nat Commun
January 2025
Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.
Bending loss is one of the serious problems for constructing nanophotonic integrated circuits. Recently, many works reported that valley photonic crystals (VPhCs) enable significantly high transmission via 120-degree sharp bends. However, it is unclear whether the high bend-transmission results directly from the valley-photonic effects, which are based on the breaking of inversion symmetry.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
School of Physics and Electrical Engineering, Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Hubei Longzhong Laboratory, Hubei University of Arts and Science, Xiangyang, Hubei, 441053, China.
Exploring valleytronics in two-dimensional materials is of great significance for the development of advanced information devices. In this study, we investigate the valley polarization and electronic properties of V-doped 2H-phase Janus MoSeTe by using first-principles calculations. Our results reveal a remarkable valley spin splitting up to 60 meV, driven by the breaking of time-reversal symmetry due to the magnetic effect of V 3d orbitals.
View Article and Find Full Text PDFData Brief
February 2025
Estación Experimental de Aula Dei, EEAD - CSIC, Ave. Montañana 1005, 50059 Zaragoza, Spain.
The dataset [1] hosts pedological info and images of the lands -locally known as - of the outcropping gypsiferous core of the Barbastro-Balaguer anticline (Fig. 1). It stands out in the landscape for the linear reliefs due to outcrops of dipping strata with differential resistance to erosion, and also because of its whitish color (Fig.
View Article and Find Full Text PDFACS Nano
January 2025
Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan.
Interlayer excitons (IXs) in the heterostructure of monolayer transition metal dichalcogenides (TMDs) are considered as a promising platform to study fundamental exciton physics and for potential applications of next generation optoelectronic devices. The IXs trapped in the moiré potential in a twisted monolayer TMD heterostructure such as MoSe/WSe form zero-dimensional (0D) moiré excitons. Introducing an atomically thin insulating layer between TMD monolayers in a twisted heterostructure would modulate the moiré potential landscape, thereby tuning 0D IXs into 2D IXs.
View Article and Find Full Text PDFSmall
January 2025
Center of Quantum Materials and Devices, College of Physics, Chongqing University, Chongqing, 401331, China.
Spin-orbit coupling (SOC) induced nontrivial bandgap and complex Fermi surface has been considered to be profitable for thermoelectrics, which, however, is generally appreciable only in heavy elements, thereby detrimental to practical application. In this study, the SOC-driven extraordinary thermoelectric performance in a light 2D material Fe₂S₂ is demonstrated via first-principles calculations. The abnormally strong SOC, induced by electron correlation through 3d orbitals polarization, significantly renormalizes the band structures, which opens the bandgap via Fe 3d orbitals inversion, exposes the second conduction valley with weak electron-phonon coupling, and aligns the energy of Fe 3d and S 3p orbitals with divergent momentum in valence band.
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