Performance improvement of blue InGaN light-emitting diodes with a specially designed n-AIGaN hole blocking layer

Blue InGaN light-emitting diodes （LEDs） with a conventional electron blocking layer （EBL）, a common n-A1GaN hole blocking layer （HBL）, and an n-A1GaN HBL with gradual A1 composition are investigated numerically, which involves analyses of the carrier concentration in the active region, energy band diagram, electrostatic field, and internal quantum efficiency （IQE）. The results indicate that LEDs with an n-AIGaN HBL with gradual AI composition exhibit better hole injection efficiency, lower electron leakage, and a smaller electrostatic field in the active region than LEDs with a conven tional p-A1GaN EBL or a common n-A1GaN HBL. Meanwhile, the efficiency droop is alleviated when an n-A1GaN HBL with gradual A1 composition is used.     

Performance improvement of GaN-based light-emitting diode with a p-InAIGaN hole injection layer

The characteristics of a blue light-emitting diode （LED） with a p-InA1GaN hole injection layer （HIL） is analyzed numerically. The simulation results indicate that the newly designed structure presents superior optical and electrical performance such as an increase in light output power, a reduction in current leakage and alleviation of efficiency droop. These improvements can be attributed to the p-InA1GaN serving as hole injection layers, which can alleviate the band bending induced by the polarization field, thereby improving both the hole injection efficiency and the electron blocking efficiency.     

A proposed U.S./China theoretical/experimental collaborative effort on baryon resonance extraction

In this paper we discuss the reasons for our work towards establishing a new collaboration between Jefferson Lab （JLab） and the Institute of High Energy Physics （IHEP） in Beijing. We seek to combine experimentalists and theorists into a dedicated group focused on better understanding the current and future data from JLab and from the Beijing Electron Positron Collider （BEPC）. Recent JLab results on the extraction of single- and double-polarization observables in both the lπ- and 2π-channel show their high sensitivity to small production amplitudes and therefore their importance for the extraction of resonance parameters. The Beijing Electron Spectrometer （BES） at the BEPC has collected high statistics data on J/ψ production. Its decay into baryon-antibaryon channels offers a unique and complementary way of probing nucleon resonances. The CEBAF Large Acceptance Spectrometer, CLAS, has access to N＊ form factors at high Q2 which is advantageous for the study of dynamical properties of nucleon resonances, while the low-background BES results will be able to provide guidance for the search for less-dominant excited states at JLab. Moreover, with the recently approved experimental proposal Nucleon Resonance Studies with CLAS12 and the high-quality data streaming from BES-Ⅲand CLAS, the time has come for forging a new Trans-Pacific collaboration of theorists and experimentalists on NSTAR physics.     

Influence of the photon beam position on incident SR intensity at the SXMCD endstation

A small fluctuation of the photon beam position will affect the intensity and polarization characteristics of synchrotron radiation （SR） when it enters an endstation through the related beamline. In this paper, by changing the electron orbit equilibrium position in the vertical direction, we have measured the corresponding changes in the absorption strength of the SR with a gold mesh in different chopper aperture positions. It is found that for three aperture positions, the absorption intensity of the gold mesh shows a good Gaussian distribution as the photon beam position moves, while the ratio of the SR intensity passing through the upper and lower apertures shows a monotonous variation. This suggests a new method for estimating the circular polarization degree of SR originating from the bending magnet based on our current measurement.     

Further investigations of the low-lying electronic states of AsO~+ radical

The high level quantum chemistry ab inito multi-reference configuration interaction （MRCI） method with large V5Z basis set is used to calculate the spectroscopic properties of the 15 A-S electronic states （X1∑＋, A I П, 1 △, 1 ∑, 3∑＋, 3П, 3△, 3△ , 5∑＋, 5П, 5△, 1П （II）, ofAsO＋ radical correlated to the dissociation limit As＋（3pg） ＋ O（3pg） and As＋（IDg） ＋ O（1Dg）. In order to obtain better potential curves and more accurate spectroscopic properties, the Davidson modification is taken into account. With the potential energy curves （PECs） determined here, vibrational levels G（v） and inertial rotation constants Bu are computed for all the bound electronic states when the rotational quantum number J equals zero （J = 0）. Except for the states X1∑＋, A1П , it is the first time that the multi-reference configuration calculation has been used on the 13 A-S electronic states of the AsO＋ radical. The potential energy curves of all the A-S electronic states are depicted according to the avoided crossing rule of the same symmetry. Spin-orbit coupling effect （SOC） is introduced into the states X1 ∑＋, A1 П, 3П to consider its effects on the spectroscopic properties. Transition dipole moments （TDMs） from A1П 1, 3 П1 states to the ground state X1∑0＋ are predicted as well.     

Multi-mode Coherent-Entangled State Representation and Its Applications

We introduce the so-called coherent-entangled state （CES） in the four-mode Fock space, which makes up a new quantum mechanical representation owing to completeness relation and orthogonal property. Its standard Schmidt decomposition and experimental generation using beam-splitter （BS） are proposed. In addition, its applications in quantum optics are presented. Finally, we extend it to multi-mode case and discuss some applications, too.     

An iterative analytic–numerical method for scattering from a target buried beneath a rough surface

An efficiently iterative analytical-numerical method is proposed for two-dimensional （2D） electromagnetic scattering from a perfectly electric conducting （PEC） target buried under a dielectric rough surface. The basic idea is to employ the Kirchhoff approximation （KA） to accelerate the boundary integral method （BIM）. Below the rough surface, an iterative system is designed between the rough surface and the target. The KA is used to simulate the initial field on the rough surface based on the Fresnel theory, while the target is analyzed by the boundary integral method to obtain a precise result. The fields between the rough surface and the target can be linked by the boundary integral equations below the rough surface. The technique presented here is highly efficient in terms of computational memory, time, and versatility. Numerical simulations of two typical models are carried out to validate the method.     

O（αsV2） correction to J/ψ plus ηc production in e＋e-annihilation at √s=10.6 GeV

Based on the nonrelativistic QCD factorization approach, O（αsv2） corrections to J/ψ plus ηc production in e＋e- annihilation at √s= 10.6 GeV are calculated in this work. The numerical results show that the correction at αsv2 order is only about a few percent of the total theoretical result. This indicates that the perturbative expansions become convergent and that a higher order correction will be smaller. The uncertainties from the long-distance matrix elements, renormalization scale and the measurement in the experiment are also discussed. Our result is in agreement with the previous result by Jia.     

Abnormal magnetic behaviors induced by the antisite phase boundary in LaeNiMnO6

The ferromagnetic semiconductor La2NiMnO6 （LNMO） has recently received much attention due to its high Curie temperature （Tc 280 K）, which is close to room temperature. We prepared single-phase LNMO polycrystaUine samples and investigated the temperature- and field-dependent magnetic behaviors of bulk LNMO. Between Tc and T＊ = 300 K, we observed upward and downward deviations from the Curie-Weiss law for high and low magnetic fields, respectively. From the electron spin resonance results, we can exclude the existence of the Griffiths phase. On the contrary, our results indicate that the abnormal magnetic behaviors might be induced by antisite phase boundaries with antiferromagnetic interaction.     

Improved device reliability in organic light emitting devices by controlling the etching of indium zinc oxide anode

A controllable etching process for indium zinc oxide （IZO） films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices （OLEDs）, a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide （ITO） anode etched by a conventional strong etchant of aqua regia.     

Spectral analysis of the UFBG-based acousto optical modulator in V–I transmission matrix formalism

In this study, the V-I transmission matrix formalism （V-I method） is proposed to analyze the spectrum characteristics of the uniform fiber Bragg grating （FBG）-based acousto--opfic modulators （UFBG-AOM）. The simulation results demon- strate that both the amplitude of the acoustically induced strain and the frequency of the acoustic wave （AW） have an effect on the spectrum. Additionally, the wavelength spacing between the primary reflectivity peak and the secondary reflectivity peak is proportional to the acoustic frequency with the ratio 0.1425 nm/MHz. Meanwhile, we compare the amount of calculation. For the FBG whose period is M, the calculation of the V-I method is 4 × （2M-l） in addition/subtraction, 8 × （2M - 1） in multiply/division and 2M in exponent arithmetic, which is almost a quarter of the multi-film method and transfer matrix （TM） method. The detailed analysis indicates that, compared with the conventional multi-film method and transfer matrix （TM） method, the V-I method is faster and less complex.     

Measurement-induced disturbance between two atoms in Tavis-Cummings model with dipole dipole interaction

Quantum correlation, measured by measurement-induced disturbance （MID）, between two two-level atoms is investi- gated in detail in Tavis-Cummings model with dipole--dipole interaction （DDI）. We find that MID can be determined only by the dipole-dipole interaction between the two atoms when the cavity and atoms are at resonance. Moreover, DDI will have different effects on MID for two different kinds of initial states.     

Electrical and dielectric properties of Al/p-Si and Al/perylene/p-Si type diodes in a wide frequency rangeElectrical and dielectric properties of Al/p-Si and Al/perylene/p-Si type diodes in a wide frequency rangeElectrical and dielectric properties of Al/p-Si and Al/perylene/p-Si type diodes in a wide frequency range

The perylene （C20H12） layer effect on the electrical and dielectric properties of Al/p-Si （MS） and Al/perylene/p-Si （MPS） diodes have been investigated and compared in the frequency range of 0.7 kHz-2 MHz. Experimental results show that C-V characteristics give an anomalous peak for two structures at low frequencies due to interface states （Nss） and series resistance （Rs）. The increases in C and G/o3 at low frequencies confirm that the charges at interface can easily follow an ac signal and yield excess capacitance and conductance. The frequency-dependent dielectric constant （er） and dielectric loss （e＇） are subtracted using C and G/co data at 1.5 V. The eI and e＂ values are found to be strongly dependent on frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. Plots of ln（o＇ac）-ln（w） for two structures have two linear regions, with slopes of 0.369 and 1.166 for MS, and of 0.077 and 1.061 for MPS, respectively. From the C 2-V characteristics, the doping acceptor atom concentration （NA） and barrier height （,~） for Schottky barrier diodes （SBDs） 1.303 ~ 1015 cm-3, and 1.10 and I. 13 eV, respectively. of MS and MPS types are also obtained to be 1.484 ~ 1015 and     

XYZ particles at Belle

In this paper, I review recent progress in the study of the XYZ particles at Belle. I only focus on studies with charmonium and one or more light mesons in the final states. This covers the X（3872）, X（3915）, Y（4140）, X（4350）, and the charged Z states.     

Generalized Wronskian Solutions to Modified Korteweg-de Vries Equation via Its Backlund Transformation

In the paper we discuss the Wronskian solutions of modified Korteweg-de Vries equation （mKdV） via the Backlund transformation （BT） and a generalized Wronskian condition is given, which allows us to substitute an arbitrary coefficient matrix in the GN （t） for the original diagonal one.     

Ab initio MRCI＋Q study on potential energy curves and spectroscopic parameters of low-lying electronic states of CS＋

Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states have not been well investigated. In this paper, the electronic states of CS＋ are studied by employing the internally contracted multireference configuration interaction method, and taking into account relativistic effects （scalar plus spin–orbit coupling）. The spin–orbit coupling effects are considered via the state-interacting method with the full Breit–Pauli Hamiltonian. The potential energy curves of 18 Λ–S states correlated with the two lowest dissociation limits of CS＋ molecular ion are calculated, and those of 10 lowest Ω states generated from the 6 lowest Λ–S states are also worked out. The spectroscopic constants of the bound states are evaluated, and they are in good agreement with available experimental results and theoretical values. With the aid of analysis of Λ–S composition of Ω states at different bond lengths, the avoided crossing phenomena in the electronic states of CS＋ are illuminated. Finally, the single ionization spectra of CS （X1Σ＋） populating the CS＋（X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋） states are simulated. The vertical ionization potentials for X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋ states are calculated to be 11.257, 12.787, 12.827, and 15.860 eV, respectively, which are accurate compared with previous experimental results, within an error margin of 0.08 eV~0.2 eV.     

Fabrication and properties of high performance YBa_2Cu_3O_(7-δ) radio frequency SQUIDs with step-edge Josephson junctions

We describe the fabrication of high performance YBa2Cu3O7-δ（YBCO） radio frequency（RF） superconducting quantum interference devices（SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3（LAO） substrates by employing stepedge junctions（SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47°to 61°, which is steep enough to ensure the formation of grain boundaries（GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition（PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH.Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/Φ0, a white flux noise of 29 μΦ0/（Hz）^1/2, and the magnetic field sensitivity as high as 80 fT/（Hz）^1/2.These devices have been applied in magnetocardiography and geological surveys.     

Effects of BaCu（B2Os） addition on sintering temperature and microwave dielectric properties of BasNb4O15-BaWO4 ceramics

The effects of BaCu（B2Os） （BCB） addition on the microstructure, phase formation, and microwave dielectric proper- ties of BasNb4015-BaWO4 ceramic are investigated. As a sintering aid, BaCu（B2Os） ceramic could effectively lower the sintering temperature of BasNb4015-BaWO4 ceramic from 1100 ℃ to 950 ℃ due to the liquid-phase effect. Meanwhile, BaCu（B2Os） addition effectively improves the densification of BasNb4015-BaWO4 ceramic and significantly influences the microwave dielectric properties. X-ray diffraction analysis reveals that BasNb4015 and BaWO4 coexist with no crystal phase of BaCu（B2Os） in the sintered ceramics. The BasNb4015-BaWO4 ceramics with 1.0 wt% BaCu（B2Os） sintered at 950 ℃ for 2 h presents good microwave dielectric properties of er = 19.0, high Q× f of 33802 GHz and low vf of 2.5 ppm/℃.     

Exact Solutions to （2＋1）-Dimensional Kaup-Kupershmidt Equation

In this paper, by using the symmetry method, the relationships between new explicit solutions and old ones of the （2＋1）-dimensional Kaup-Kupershmidt （KK） equation are presented. We successfully obtain more general exact travelling wave solutions for （2＋ 1）-dimensional KK equation by the symmetry method and the （G1/G）-expansion method. Consequently, we find some new solutions of （2＋1）-dimensional KK equation, including similarity solutions, solitary wave solutions, and periodic solutions.     

Exact Solutions of （2＋1）-Dimensional Boiti-Leon-Pempinelle Equation with （G′/G）-Expansion Method

In this paper, we construct exact solutions for the （2＋1）-dimensional Boiti-Leon-Pempinelle equation by using the （G′/G）-expansion method, and with the help of Maple. As a result, non-travelling wave solutions with three arbitrary functions are obtained including hyperbolic function solutions, trigonometric function solutions, and rational solutions. This method can be applied to other higher-dimensional nonlinear partial differential equations.