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We present a simple hot press-based method for processing La(Fe,Si)13-based compounds consisting of La–Fe–Co–Si–C particles and phenolic resin. The magnetic entropy change ΔS per unit mass for the LaFe10.87Co0.63Si1.5C0.2/phenolic resin compounds have nearly the same magnitude with the base materials. With the content of phenolic resin of 5.0 wt%, the compound conductivity is 3.13 W⋅m−1⋅K−1. In order to measure the cooling performance of La(Fe,Si)13-based compounds, the La(Fe11.6–x Co x )Si1.4C0.15 (x = 0.60, 0.65, 0.75, 0.80, 0.85)/phenolic resin compounds were pressed into thin plates and tested in a hybrid refrigerator that combines the active magnetic refrigeration effect with the Stirling cycle refrigeration effect. The test results showed that a maximum cooling power of 41 W was achieved over a temperature span of 30 K.

In this corrigendum, we point out that the photon energy 16.3 eV is written as 13.6 eV by mistake in some statements in the article 2022 New J. Phys. 24 093019.

The angular distributions of the photoelectrons in ionization of hydrogen atom by both circularly and linearly polarized intense extreme ultraviolet (XUV) attosecond pulse are investigated by numerically solving the time-dependent Schrödinger equation. We clearly identify nonperturbative features in studying the asymmetrical photoelectron angular distributions in the polarization plane for the XUV photon energy (16.3 eV) close to the ionization threshold, while such nonperturbative features are absent for higher photon energy (36 eV) in the same pulse intensity region. In addition to the carrier-envelope phase (CEP) dependence, the ejection asymmetry of the photoelectron is also sensitive to the relative phases of transition amplitudes in absorbing one photon and two photons. As a consequence, the CEPs corresponding to the maximal (or zero) asymmetry obviously vary as the pulse intensity increases in a moderately large region from 1 × 1015 W cm−2 to 30 × 1015 W cm−2. We attribute the intensity dependence of the transition amplitude phases to a consequence of the depletion of population as well as the Stark energy shift of the initial state. We show that the relative phases of transition amplitudes can be precisely decoded from the pulse intensity dependence of the ejection asymmetry and those phases are insensitive to the ellipticity of the laser pulse.

One of the major advantages of utilizing atmospheric pressure plasma processing (APPP) technology to fabricate ultra-precision optics is that there is no subsurface damage during the process. In APPP, the removal footprint and removal rate are critical to the capability and efficiency of the figuring of the optical surface. In this paper, an atmospheric plasma torch, which can work in both remote mode and contact mode, is presented. The footprints and the removal rates of both modes are compared by profilometer measurements. The influences of process recipes and substrate thickness for both modes are investigated through a series of experiments. When the substrate is thinner than 12 mm, the removal rate in contact mode is higher. However, the removal rate and width of the footprint decrease dramatically as the substrate thickness increases in contact mode.

A series of Ga doping perovskite cobaltite La2/3Sr1/3(Co1−yGay)O3 (y = 0, 0.1, 0.2, 0.3 and 0.4) are prepared by the standard solid-state reaction method. Their magnetic properties and Co ions spin state transitions are studied. Upon doping, no appreciable structure changes can be found. However, the corresponding Curie temperature sharply decreases and the magnetization is greatly reduced, indicating that Ga doping destroys the ferromagnetic interaction in the system. In addition, the high temperature magnetization data follow the Curie–Weiss law. At least one kind of Co ions (Co3+ or Co4+) favours the mixed spin state, and most Co ions are at the lower spin state (low and intermediate state). With increasing Ga content, more Co ions transit to the higher spin state.

The melting and freezing processes of CuN (N = 180, 256, 360, 408, 500, 628 and 736) nanoclusters are simulated by using micro-canonical molecular dynamics simulation technique. The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CuN nanoclusters for the first time.

This paper presents a novel dielectric elastomer actuator (DEA) with three stable states. By introducing magnetic forces and coupling them with two cone dielectric elastomer (DE) films, an inherent tristability for the DEA is obtained with a compact design. It is easy to switch between the three stable states by controlling the voltages applied to the DE films. A theoretical model of the system's potential energy that contains the free energy of the DEs and the potential energy of the applied magnetic field was developed for the tristable mechanism. The experimental results demonstrate that controllable transitions between the three stable states can be achieved with this design by applying over-critical voltages to the various DE films. The maximum dynamic range of the DEA can exceed 53.8% of the total length of the device and the DE's creep speed was accelerated under the action of the magnetic field.

In this paper, a thin tensile GaAs interlayer was used to obtain a regular arrangement of InAs quantum dots on an InP substrate by low-pressure metal-organic chemical vapour deposition (LP-MOCVD). Photoluminescence (PL) spectra, atomic force microscopy image and Raman spectra have been investigated. Some theoretical calculations in the PL and Raman spectra have been performed. The conclusions coincide well with our experiment results.

The ground state behaviour of GaAs quantum dots with N = 2-6 electrons in a magnetic field of B = 0-5 T is investigated in the Hartree-Fock (HF) approximation, and then the correlation effects are taken into account via a local-density-functional approach. It is found that in the HF approximation the dot electrons have already been in spin-polarized states at small B, even at B = 0 T for most cases. However when the electron correlations are included, all the spin-polarized states at small B are suppressed and the ground states of all cases around B = 0 are normal states with S = 0 or ½ for even or odd number of electrons. As B is increased to 1.83-2.64 T the ground states will directly transit from normal states to their corresponding fully spin-polarized states.

The correlation energies of quantum dot electrons with harmonic model interactions in a large magnetic field are studied by comparing the Hartree - Fock (HF) ground state energies with the exact values. The results for GaAs quantum dots show that the correlation corrections to the ground state energies are very small, only 0.1 - 0.8% for N = 2 - 7 electrons. The changes of the correlation energies with the electron - electron interaction strength are also studied. It is shown that the correlation energies increase rapidly with for larger N, but are limited by the condition for a stable dot. The comparison of the HF and the exact energies, varying with the total angular momentum, reveals that the correlation energies take their minima at the so-called `magic' angular momenta that exist in the cases of Coulomb interactions.

The low-lying energy levels of three-electron quantum dots in a magnetic field are calculated by both the Hartree-Fock (HF) and the numerical diagonalization methods. Many-body effects on the energy level structure are investigated by comparing the results from these two approaches. It is found that many-body interactions can apparently change the relative positions of the low-lying energy levels, especially at larger angular momentum quantum numbers, and the relative changes of the levels almost have nothing to do with the external magnetic field, but linearly depend on the dot size.

ZnO thin films have been grown on C-plane sapphire substrates by plasma-enhanced metal-organic chemical vapour deposition. The samples are then annealed at a higher temperature. The resistivity, concentration of electron, mobility and optically pumped threshold of both as-grown and annealed films are investigated. Furthermore, their structural and optical properties are also examined with x-ray diffraction, emission spectra and optical transmission spectra. The results indicate that the quality of ZnO thin films can be improved by annealing.

Room temperature photoluminescence (PL) spectra of InAs self-assembled quantum dots (QDs) deposited on a GaAs/InP and InP substrate are investigated. From the PL spectra, we find that the peak position of InAs QDs appears redshift from 0.795 to 0.785 eV after we insert a thin tensile GaAs layer between InAs QD layer and InP buffer layer. In order to explain this phenomenon in theory, we examine the strain tensor in InAs quantum dots by using a valence force field model and use a five-band kp formalism to obtain the electronic structure. The calculated results show that the ground transition energy decreases from 0.789 to 0.780 eV when the thin GaAs layer is inserted. Therefore, the PL peak position should appear redshift as shown in the experiment.

In this paper the dynamical properties of evolutionary network, especially the types of final states of the network, have been studied analytically and/or numerically.

The magnetism and magnetocaloric effect in Er1 − xGdxCoAl (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1) were investigated. The Er1 − xGdxCoAl compounds were synthesized by arc melting. With the increasing Gd content, the Neel temperature (TN) linearly increases from 14 K to 102 K, while the magnetic entropy change (−ΔSM) tends to decrease nonmonotonously. Under the field change from 0 T to 5 T, the −ΔSM of the compounds with x = 0.2–1 are stable around 10 J/kg K, then a cooling platform between 20 K and 100 K can be formed by combining these compounds. For x = 0.6, 0.8, 1.0, the compounds undergo two successive magnetic transitions, one antiferromagnetism to ferromagnetism and the other ferromagnetism to paramagnetism, with increasing temperature. The two continuous magnetic transitions in this series are advantageous to broaden the temperature span of half-peak width (δT) in the −ΔSM−T curve and improve the refrigeration capacity.

Epitaxial evolution of buried cracks in a strain-controlled AlN/GaN superlattice interlayer (IL) grown on GaN template, resulting in crack-free AlGaN/GaN multiple quantum wells (MQW), was investigated. The processes of filling the buried cracks include crack formation in the IL, coalescence from both side walls of the crack, build-up of an MQW-layer hump above the cracks, lateral expansion and merging with the surrounding MQW, and two-dimensional step flow growth. It was confirmed that the filling content in the buried cracks is pure GaN, originating from the deposition of the GaN thin layer directly after the IL. Migration of Ga adatoms into the cracks plays a key role in the filling the buried cracks.

Motivated by the latest improved measurements of B-meson decays, we make a comprehensive analysis of the impact of a family non-universal $Z^{\prime}$ boson on $B_s-\bar{B}_s$ mixing and two-body hadronic B-meson decays, all being characterized by the quark-level $b\to s$ transition. Explicitly 22 decay modes and the related 52 observables are considered, and some interesting correlations between them are also carefully examined. Firstly, the allowed oases of $b-s-Z^{\prime}$ coupling parameters $|B^{L,R}_{sb}|$ and $\phi^{L,R}_s$ are extracted from $B_s-\bar{B}_s$ mixing. Then, in the "SM limit"~({\it i.e.,} no new types of $Z^{\prime}$-induced four-quark operators arise compared to the SM case), we study the $Z^{\prime}$ effects on $B\to\pi K$, $\pi K^{\ast}$ and $\rho K$ decays. It is found that a new weak phase $\phi^{L}_s\sim -90^{\circ}$ is crucial for resolving the observed "$\pi K$ CP puzzle" and the allowed oases of the other $Z^{\prime}$ coupling parameters are also strongly restricted. Moreover, the $Z^{\prime}$ effects on $\bar{B}_s\to K K$, $K K^{\ast}$ and $\pi^0 \phi$ decays, being induced by the same quark-level $b\to s q\bar{q}~(q=u,d)$ transitions, are also investigated. Especially, it is found that the decay $\bar{B}_s \to \pi^0 \phi$, once measured, would play a key role in revealing the observed "$\pi K$ CP puzzle" and probing possible new physics hints. Finally, to check the non-universality of $Z^{\prime}$ couplings to light-quark pairs, we have studied the $B\to \phi K$ decays in detail and found that the left-handed $s-s-Z^{\prime}$ coupling is different from the $d-d-Z^{\prime}$ one, which is due to the large $A_{CP}^{dir}(B^-\to\phi K^-)$ reported by the BaBar collaboration., Comment: 38 pages, 11 figures; To appear in JPG

A sizable excess with respect to the SM expectation has been reported recently by the BaBar collaboration in the decay rates B -> D(*) Tau Nu, normalized by the corresponding light lepton modes. A violation of lepton flavor universality as suggested by this excess could be due to a charged Higgs mediating these processes at tree level. In this talk we analyze the implications of the observed excess within the framework of two-Higgs-doublet models, considering also the bounds from other semileptonic and leptonic decays of B and D(s) mesons. Prospects for B -> D(*) Tau Nu decays at future Super-Flavor Factories are also discussed.

First-principles calculations based on spin density functional theory are performed to study the spin-resolved electronic properties of ZnO codoped with Cu and N. (Cu, N)-codoped ZnO exhibits magnetism, and the total magnetic moment mainly originates from the p—d hybridization of Cu—N and Cu—O as well as p—p coupling interaction between N and O at the Fermi level. The Zn34Cu2O35N1 favors energetically a ferromagnetic ground state due to the existence of stable Cu—N—Cu complex. These results imply that the (Cu, N)-codoped ZnO is a promising dilute magnetic semiconductor free of magnetic precipitates, which could broaden the horizon of currently known magnetic systems.

We study two flux qubits with a parameter coupling scenario. Under the rotating wave approximation, we truncate the 4-dimensional Hilbert space of a coupling flux qubits system to a 2-dimensional subspace spanned by two dressed states vertical bar 01 > and vertical bar 10 >. In this subspace, we illustrate how to generate an Aharnov-Anandan phase, based on which, we can construct a NOT gate (as effective as a C-NOT gate) in this coupling flux qubits system. Finally, the fidelity of the NOT gate is also calculated in the presence of the simulated classical noise.

We investigate epitaxy of AlN layers on sapphire substrates by molecular beam epitaxy. It is found that an atomically flat surface can be obtained under Al-rich conditions at growth temperature of 780°C. However, the growth window to obtain an Al-droplet-free surface is too narrow to be well-controlled. However, the growth window can be greatly broadened by increasing the growth temperature up to 950°C, where an Al-droplet-free surface with a step-flow feature is obtained due to the enhanced re-evaporization rate and migration ability of Al adatoms. The samples grown at the higher temperature also show a higher crystalline quality than those grown at lower temperatures.

Mesa-structured submicron intrinsic Josephson junctions are successfully fabricated and well characterized on underdoped Bi2Sr2Ca1−xYxCu2O8+δ single crystals with a Tc of 80 K. Tunneling spectra at the temperatures ranging from 4.2 K to 295 K are measured. A pulse technique is used to reduce sample heating for the measurement near pseudogap opening temperature T* ~ 280 K. Our experimental results show that the superconducting gap, the peak-dip separation, and the pseudogap opening temperature are all increased as compared with those from near optimally doped samples, which requires further theoretical analysis in the future.