Communications in Physics

Insights into the structural, electronic and magnetic properties of gold clusters: Comparison between Au12Cr and Au12Mo clusters

Ngo Thi Lan — 2024-11-27

Modification of the chemical and physical properties with respect to element component in atomic clusters has paved the way for great potential in both fundamental study and applications. An investigation on the structure, stability and magnetic properties of gold clusters doped by Cr and Mo (Au₁₂Cr and Au₁₂Mo) is discussed in this work, using the density functional theory calculation. The bond strength of AuM dimers governs the globally minimum structural evolution in the Au₁₂M clusters, which can be classified into two principal forms: the icosahedral (Mo dopant) and the cone-like structures (Cr dopant). The average binding and dissociation energies indicate that the enhanced stability of cluster stem from the contribution of Cr/Mo atom. The molecular orbital (MO) diagram and the spin distribution are computed to better understand the electronic configuration and magnetic behavior of the studies clusters. The Au₁₂Cr has a significant magnetic moment of 4 µ_B. Conversely, the magnetic moment is completely quenched in Au₁₂Mo cluster. Furthermore, the IR spectra of Au₁₂M are also predicted.

A Design of high efficiency and wideband dual-functional metasurface for polarization conversion and asymmetric transmission

Hoa Nguyen Thi Quynh — 2024-10-29

A wideband and high-efficiency bi-functional metasurface for polarization conversion and asymmetric transmission (AT) based on the gratings/ polarization converter/gratings structure is proposed. The proposed metasurface structure consists of a two double-split ring structure array sandwiched by two orthogonal metallic sub-wavelength gratings. Using two orthogonal metallic
sub-wavelength gratings, the proposed metasurface reveals excellent AT effect and nearly perfect polarization conversion performance for linearly polarized waves. The proposed metasurface achieves a polarization conversion ratio (PCR) of above 0.99 from 3.7 GHz to 20.2 GHz with a relative bandwidth (RBW) of 138% and an AT parameter of over 0.9 from 5.8 GHz to 17 GHz with
an RBW of 99.5%. Moreover, the proposed metamaterial maintains high PCR and AT performance for a wide range of incident angles. Due to its excellent features, such as the wideband and high efficiency of both PCR and AT performances, the proposed bi-functional metasurface can be useful for promising applications such as polarization imaging. radar, radiometer, and transmission.
array antennas.

New Physics in the 3-3-1 models

Hoang Ngoc Long — 2024-08-30

Two main ingredients of current particle physics such as local gauge symmetry and mass generation via the Higgs mechanism being basic ground of the Standard Model are widely confirmed by experimental data. However, some problems such as neutrino masses, dark matter, baryon asymmetry of Universe have clearly indicated that the Standard Model cannot be the ultimate theory of nature. To surpass the mentioned puzzles, many extensions of the Standard Model (called beyond Standard Model) have been proposed. Among beyond Standard Models, the 3-3-1 models have some intriguing features and they get wide attention. The pioneer models develop in some directions. In this paper, new main versions of the 3-3-1 models and their consequences are presented.