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In the framework of nonlinear wave optics, we report the evolution process of a dipole breathing wave in lossy nonlocal nonlinear media based on the nonlocal nonlinear Schrödinger equation. The analytical expression of the dipole breathing wave in such a nonlinear system is obtained by using the variational method. Taking advantage of the analytical expression, we analyze the influences of various physical parameters on the breathing wave propagation, including the propagation loss and the input power on the beam width, the beam intensity, and the wavefront curvature. Also, the corresponding analytical solutions are obtained. The validity of the analysis results is verified by numerical simulation. This study provides some new insights for investigating beam propagation in lossy nonlinear media [ABSTRACT FROM AUTHOR]

The weakly bound nucleus 29F locates near the neutron drip line. Experiments have confirmed that it is the heaviest two-neutron halo nucleus discovered up to now. To understand the halo structure in 29F, we explore the weakly bound and resonant levels close to the Fermi surface with the complex momentum representation method. Not only the narrow resonances and the broad resonances. Since the broad resonance 2 p 3/2 is disclosed, the p âˆ' f inversion and N = 20 shell gap quenching are found. The last valence neutron can occupy the weakly bound level 1/2[310], composed mainly of p 3/2â€"component, or the 1/2[211], composed mainly of s 1/2â€"component. Since the wavefunctions of p and s â€"components extend to a large range in the coordinate space, which results in the density distributions of the levels 1/2[310] and 1/2[211] being considerably diffuse. This is the most likely cause of halo formation in 29F and the halo may be formed by the p â€"component, s â€"component, or their mixtures by pairing correlations. [ABSTRACT FROM AUTHOR]

Two-dimensional electron gas (2DEG) with high electron mobility is highly desired to study the emergent properties and to enhance future device performance. Here we report the formation of 2DEG with high mobility at the interface between rock-salt BaO and perovskite SrTiO3. The interface consists of the ionically compensated BaO1 â€" δ layer and the electronically compensated TiO2 layer, which is demonstrated as a perfect interface without lattice mismatch. The so-formed interface features metallic conductivity with ultralow square resistance of 7.3 Ă— 10âˆ'4 Ω/â—» at 2 K and high residual resistance ratios R 300 K/ R 2 K up to 4200. The electron mobility reaches 69000 cm2â‹...Vâˆ'1â‹...sâˆ'1 at 2 K, leading to Shubnikovâ€"de Haas oscillations of resistance. Density functional theory calculations reveal that the effective charge transfers from BaO to the Ti 3 dxy orbital occur at the interface, leading to the conducting TiO2 layer. Our work unravels that BaO can adapt itself by removing oxygen to minimize the lattice mismatch and to provide substantial carriers to SrTiO3, which is the key to forming 2DEGs with high mobility at the interfaces. [ABSTRACT FROM AUTHOR]

An ultra-wideband 2-bit coding metasurface is designed for radar cross-section (RCS) reduction. The design process is presented in detail, in which a polarization conversion metasurface (PCM) is first proposed. The proposed PCM can realize ultra-wideband circular polarization (CP) maintaining reflection. Moreover, Pancharatnam-Berry (PB) phase will be generated in the co-polarized reflection coefficient by rotating the metallic patches in its unit cells. Thus, based on the PCM, the four coding elements of a 2-bit coding metasurface are constructed using PB phase, and an ultra-wideband PB 2-bit coding metasurface is proposed according to an appropriate coding sequence. The simulated and experimental results show that the coding metasurface has obvious advantages of wideband and polarization-insensitivity. Compared to a metallic plate of the same size, it can achieve more than 10 dB RCS reduction in the frequency band from 9.8 GHz to 42.6 GHz with a relative bandwidth of 125.2% under normal incidence with arbitrary polarizations. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals material is a focus of research for its widespread application in optoelectronics, memories, and spintronics. The ternary compound Nb2SiTe4 is a van der Waals semiconductor with excellent air stability and small cleavage energy, which is suitable for preparing a few layers counterpart to explore novel properties. Here, properties of bulk Nb2SiTe4 with large in-plane electrical anisotropy are demonstrated. It is found that hole carriers dominate at a temperature above 45 K with a carrier active energy of 31.3 meV. The carrier mobility measured at 100 K is about 213 cm2⋅V−1⋅s−1 in bulk Nb2SiTe4, higher than the reported results. In a thin flake Nb2SiTe4, the resistivity ratio between the crystalline axes of a and b is reaching about 47.3 at 2.5 K, indicating that there exists a large anisotropic transport behavior in their basal plane. These novel transport properties provide accurate information for modulating or utilizing Nb2SiTe4 for electronic device applications. [ABSTRACT FROM AUTHOR]

We investigate the structural variation and physical properties of layered La2M5As3O2 (M = Cu, Ni) compound upon Co doping. It is found that the substitution of Co ion just induces the monotonous change of lattice constants without observing the anomalous kink in superconducting La2(Cu1–xNix)5As3O2 solid-solutions. Meanwhile, this doping barely changes As–As bond length in [M5As3]2– subunit (±2%), being significantly smaller than 7% shrinkage of that in La2(Cu1–xNix)5As3O2. Therefore, the doping dependence of crystal structure exhibits similar trend with Ba1–xKxFe2As2 without the interference of As1–As2 bonding, implying that the Co substitution for Cu/Ni is hole-doped. In terms of physical property, La2(Cu1–xCox)5As3O2 turns into itinerant ferromagnetic metal, while La2(Ni1–xCox)5As3O2 shows paramagnetism and suppressed structural phase transition upon Co-doping. The distinct structural variation and absence of superconductivity provide important clues to understand the effect of As–As bond in [M5As3]2– subunit. [ABSTRACT FROM AUTHOR]