Active strong coupling of exciton and nanocavity based on GSST-WSe2 hybrid nanostructures.

The strong coupling between optical resonance microcavity and matter excitations provides a practical path for controlling light-matter interactions. However, conventional microcavity, whose functions are fixed at the fabrication stage, dramatically limits the modulation of light-matter interactions. Here, we investigate the active strong coupling of resonance mode and exciton in GSST-WSe2 hybrid nanostructures. It is demonstrated that significant spectral splitting is observed in single nanostructures, tetramers, and metasurfaces. We further confirm the strong coupling by calculating the enhanced fluorescence spectra. The coupling effect between the excited resonance and exciton is dramatically modulated during the change of GSST from amorphous to crystalline, thus realizing the strong coupling switching. This switching property has been fully demonstrated in several systems mentioned earlier. Our work is significant in guiding the study of actively tunable strong light-matter interactions at the nanoscale.

Size effects and electronic properties of zinc-doped boron clusters Zn B n (n = 1-15).

CONTEXT: To gain a deeper understanding of zinc-doped boron clusters, theoretical calculations were performed to investigate the size effects and electronic properties of zinc-doped boron clusters. The study of the electronic properties, spectral characteristics, and geometric structures of Zn B n (n = 1-15) is of great significance in the fields of semiconductor materials science, material detection, and improving catalytic efficiency. The results indicate that Zn B n (n = 1-15) clusters predominantly exhibit planar or quasi-planar structures, with the Zn atom positioned in the outer regions of the B n framework. The second stable structure of Zn B 3 is a three-dimensional configuration, indicating that the structures of zinc-doped boron clusters begin to convert from the planar or quasi-planar structures to the 3D configurations. The second low-energy structure of Zn B 15 is a novel configuration. Relative stability analyses show that the Zn B 12 has better chemical stability than other clusters with a HOMO-LUMO gap of 2.79 eV. Electric charge analysis shows that part electrons on zinc atoms are transferred to boron atoms, and electrons prefer to cluster near the B n framework. According to the electron localization function, it gets harder to localize electrons as the equivalent face value drops, and it's challenging to see covalent bond formation between zinc and boron atoms. The spectrograms of Zn B n (n = 1-15) exhibit distinct properties and notable spectral features, which can be used as a theoretical basis for the identification and confirmation of boron clusters doped with single-atom transition metals. METHODS: The calculations were performed using the ABCluster global search technique combined with density functional theory (DFT) methods. The selected low-energy structures were subjected to geometric optimization and frequency calculations at the PBE0/6-311 + G(d) level to ensure structural stability and eliminate any imaginary frequencies. To acquire more precise relative energies, we performed single-point energies calculations for the low-lying isomers of Zn B n (n = 1-15) at the CCSD(T)/6-311 + G(d)//PBE0/6-311 + G(d) level of theory. All calculations were performed using Gaussian 09 software. To facilitate analysis, we utilized software tools such as Multiwfn, and VMD.

Strong coupling of excitons and electric/magnetic toroidal dipole modes in perovskite metasurfaces.

Effective manipulation of the interactions between light and matter is crucial for the advancement of various high-performance optoelectronic devices. It is noted that the toroidal dipole resonance refers to an electromagnetic excitation that exists beyond the conventional understanding of electric and magnetic multipoles, which shows great potential for enhancing light-matter interactions. In this work, we investigate the strong coupling properties of electric toroidal dipole (ETD) and magnetic toroidal dipole (MTD) with excitons in (PEA)2PbI4 perovskite metasurfaces. The nanostructure consists of two identical nanobars on a SiO2 substrate, which support ETD and MTD responses. The strong coupling between ETD/MTD modes and perovskite excitons is achieved when adjusting oscillator strength f0, which can be charactered by the clearly anti-crossing behavior appeared in the transmission spectra. The Rabi splitting can be readily tuned by controlling f0. When f0 increases to 1.0, their Rabi splitting values reach as high as 371 meV and 300 meV, respectively. The proposed strong coupling between excitons and ETD/MTDs paves the way for large-scale, low-cost integrated polaritonic devices operating at room temperature.

Molecular Dynamics Simulations of Ether- and Ester-Linked Phospholipid Bilayers: A Comparative Study of Water Models.

Membrane dipole potential influences a variety of important biological processes involving cell membranes. Because it is quite challenging to directly measure the membrane dipole potential in experiments, molecular dynamics (MD) simulation has emerged as a powerful tool for a reasonable prediction of the dipole potential. Although MD predictions agree well with experiments about the sign of the dipole potential, the magnitude of the dipole potential varies significantly with the force field parameters. It has been shown that the positive dipole potential of phosphatidylcholine (PC) bilayer membranes would be overestimated by a nonpolarizable model owing to the treatment of many-body polarization effects in a mean-field fashion. In this work, we carried out atomistic MD simulations of the diphytanyl PC (ether-DPhPC) and diphytanoyl PC (ester-DPhPC) bilayers and made a comparative study of three different nonpolarizable water models (TIP3P, TIP4P, and TIP5P). Interestingly, we discover that the calculated dipole potential by the TIP5P model shows good agreement with the result obtained using the cryoelectron microscopy experiment, suggesting that a better description of electrostatic interactions in a nonpolarizable water model can effectively ameliorate the overestimation in the calculation of the dipole potential. In addition, our MD results show that the substitution of the ether linkage for the ester linkage of phospholipid bilayers would bring about a change in the orientation of the linkage group with respect to the bilayer normal, leading to the difference in the membrane dipole potential. Surprisingly, although water molecules provide a major contribution to the positive dipole potential, they have a limited impact on the difference of the dipole potential between the ether-DPhPC and ester-DPhPC bilayer membranes.