The top 500 results for "superconductor" are:

We investigate the dynamics of a first-order quark-hadron transition via homogeneous thermal nucleation in the two-flavor quark-meson model. The contribution of the fermionic vacuum loop in the effective thermodynamics potential and phase diagram, together with the location of the critical endpoint (CEP), is obtained in the temperature and chemical potential plane. For weak and strong first-order phase transitions, by taking the temperature as a variable, the critical bubble profiles, evolutions of the surface tension, and saddle-point action in the presence of a nucleation bubble are numerically calculated in detail when fixing the chemical potentials at $\mu=306~ \mathrm{MeV}$ and $\mu=309 ~\mathrm{MeV}$. Our results show that the system could be trapped in the metastable state for a long time as long as the temperature is between the metastable region characterized by the up and low spinodal lines. Moreover, the surface tension at criticality will rise to approximately $4~ \mathrm{MeV/fm^2}$ when the chemical potential is very high. Such a small surface tension value would favor a mixed phase in the cores of compact stars and may have an important implication in astrophysics.

It has been suggested that Ba3In2O6 might be a high-Tcsuperconductor. Experimental investigation of the properties of Ba3In2O6 was long inhibited by its instability in air. Recently epitaxial Ba3In2O6 with a protective capping layer was demonstrated, which finally allows its electronic characterization. The optical bandgap of Ba3In2O6 is determined to be 2.99 eV in-the (001) plane and 2.83 eV along the c-axis direction by spectroscopic ellipsometry. First-principles calculations were carried out, yielding a result in good agreement with the experimental value. Various dopants were explored to induce (super-)conductivity in this otherwise insulating material. Neither A- nor B-site doping proved successful. The underlying reason is predominately the formation of oxygen interstitials as revealed by scanning transmission electron microscopy and first-principles calculations. Additional efforts to induce superconductivity were investigated, including surface alkali doping, optical pumping, and hydrogen reduction. To probe liquid-ion gating, Ba3In2O6 was successfully grown epitaxially on an epitaxial SrRuO3 bottom electrode. So far none of these efforts induced superconductivity in Ba3In2O6, leaving the answer to the initial question of whether Ba3In2O6 is a high-Tcsuperconductor to be "no" thus far.

The study delves into actively controlling Fano resonance within a single-mode microstrip cavity, coupled with a split ring resonator (SRR) incorporating a varactor diode. This resonance arises from the interference between the SRR and a Fabry–Pérot cavity, resulting in a sharply asymmetric transmission spectrum. The varactor diode, situated within the SRR gap, is biased electrically via an external DC voltage source. Through manipulation of this bias voltage, both the transmission frequency and amplitude of the pronounced Fano resonance can be dynamically adjusted. Notably, a significant frequency shift of 345 MHz is achieved, accompanied by a transmission modulation depth of up to 34.2 dB. Moreover, at the Fano peak frequency of 2.65 GHz, the composite SRR-cavity structure exhibits a notable change in group delay, shifting by 21.3 ns with the bias voltage varying from 5 V to 2.6 V. These findings hold promise for the development of electrically controlled functional photonic devices, facilitating their adaptability and versatility in practical applications.

The thermal annealing effect on the morphological, structural and electrochemical properties of hydrothermal synthesized Li₄Ti₅O₁₂ / TiO₂ has been studied. Lithium titanate (Li₄Ti₅O₁₂) nanopowders are successfully synthesized by hydrothermal method using titanuim tetrabutyl and lithium hydroxide followed by thermal annealing process at different temperatures: 500 °C, 800 °C and 900 °C. The X-ray diffraction (XRD) patterns indicates the appearance of the Li₄Ti₅O₁₂ phase at a temperature above 800 °C formed after the reaction of the two phases: TiO₂ and Li₂TiO₃ which appear at 500 °C. Though, the prepared electrode by the powder annealed at 800 °C shows an initial capacity of about 173.1 mAh g⁻¹ (0.1 C), which retained at 75.6 mAh g⁻¹ after 100 cycles.

Highlights

• Li₄Ti₅O₁₂/TiO₂ nanopowders are successfully Synthesized by low temperature hydrothermal method.

• Studying the effect of Thermal annealing on the morphological, structural and electrochemical properties of hydrothermal synthesized Li₄Ti₅O₁₂/ TiO₂.

• X-ray diffraction patterns confirmed that high-purity Li₄Ti₅O₁₂ can be successfully obtained after thermal annealing ≤ 800 °C.

• Annealed powder at 800 °C shows high initial discharge capacity of 173.1 mAh g⁻¹ at 0.1 C, which retained at 75.6 mA h g⁻¹ after 100 cycles.

CORC cables are subject to large transverse compression electromagnetic forces in fusion projects. Unfortunately, the electromagnetic force exceeding its critical transverse compression load will cause an irreversible decrease in its critical current. Therefore, it is particularly important to enhance the critical transverse compression load to ensure that the critical current does not decrease during operation. The winding method of high temperature superconducting (HTS) tape on the central former is variable. So the experimental study on how to increase the critical transverse compression load of CORC cable by changing the winding method of HTS tape is carried out in this paper. Firstly, the influence law of parameters of the number of HTS tapes per layer and the number of HTS tape layers on their transverse compression performance are analysed independently. The results indicate that increasing the number of HTS tapes per layer and the number of HTS tape layers can both improve the transverse compression performance of CORC cables. Whereas, in the case of a cable with a certain critical current demand (the same total number of HTS tapes), increasing the number of HTS tape layers necessarily reduces the number of HTS tapes per layer. Therefore, in order to compare the degree of influence of the above two parameters, we conducted transverse compression experiments on multiple groups of CORC cables with different winding methods (more layers with few tapes per layer or few layers with more tapes per layer) under the same critical current demand. The results show that under the same critical current demand, choosing the winding method that reduces the number of HTS tape layers and increases the number HTS tapes per layer can effectively improve the transverse compression performance of CORC cables. A 3D multilayer CORC cable transverse compression finite element model is also established to explain the inherent reasons for the differences in transverse compression performance of CORC cables under different HTS tape winding methods.

The detection of inelastically scattered soft X-rays with high energy resolution usually requires large grating spectrometers. Recently, photoelectron spectrometry for analysis of X-rays (PAX) has been rediscovered for modern spectroscopy experiments at synchrotron light sources. By converting scattered photons to electrons and using an electron energy analyser, the energy resolution for resonant inelastic X-ray scattering (RIXS) becomes decoupled from the X-ray spot size and instrument length. In this work, we develop PAX towards high energy resolution using a modern photoemission spectroscopy setup studying Ba₂Cu₃O₄Cl₂ at the Cu L₃ edge. We measure a momentum transfer range of 24% of the first Brillouin zone simultaneously. Our results hint at the observation of a magnon excitation below 100 meV energy transfer and show intensity variations related to the dispersion of dd-excitations. With dedicated setups, PAX can complement the best and largest RIXS instruments, while at the same time opening new opportunities to acquire RIXS at a range of momentum transfers simultaneously and combine it with angle-resolved photoemission spectroscopy in a single instrument.

We propose a theoretical scheme for a one-dimensional superconducting circuit lattice system to achieve that topological phase transition and topological multi-channel transfer, which is adjusted by the asymmetric hopping modulations. The system consists of an array of coupled superconducting microwave cavities, the hopping between its can be modulated by the qubits. Here, we explore topological stages by introducing parameters to expand the hopping modulation range. We found that the energy bands in the system exhibit different structural characteristics, which can achieve topological phase switching. Meanwhile, the edge modes can undergo a flipping process, which can not only realize dual-channel topological quantum information transfer, but also can achieve four-channel. Furthermore, it is noted that the defect can induce new topological phases, which can be optimized by adjusting the hopping parameters, while disorder can only cause band fluctuations and inversions, but does not change the position and period of edge states, verifying that the edge state transport is robust. The results obtained in this work can be applied to the storage and transmission of quantum information, and have a guiding role in the future development of quantum technology.

We investigate the domain wall network in twisted bilayer graphene (TBG) under the influence of interlayer bias and screening effect from the layered structure. Starting from the continuum model, we analyze the low-energy domain wall modes within the moiré bilayer structure and obtain an analytic form representing charge density distributions of the two-dimensional structure. By computing the screened electron–electron interaction strengths both within and between the domain walls, we develop a bosonized model that describes the correlated domain wall network. We demonstrate that these interaction strengths can be modified through an applied interlayer bias, screening length and dielectric materials, and show how the model can be employed to investigate various properties of the domain wall network and its stability. We compute correlation functions both without and with phonons. Including electron–phonon coupling in the network, we establish phase diagrams from these correlation functions. These diagrams illustrate electrical tunability of the network between various phases, such as density wave states and superconductivity. Our findings reveal the domain wall network as a promising platform for the experimental manipulation of electron–electron interactions in low dimensions and the study of strongly correlated matter. We point out that our investigation not only enhances the understanding of domain wall modes in TBG but also has broader implications for the development of moiré devices.

This study uses molecular dynamics simulations to explore the mechanical properties of a nano-twinned copper–nickel alloy during indentation. We investigate the impact of twin boundary (TB) angles and spacing on the alloy's behavior. The plastic deformation process is primarily driven by dislocation generations, slips, and TB interactions, directly affecting the alloy's hardness. Significant findings include: (1) hardness initially decreases, then increases with increasing TB angle θ, and for TB spacing d greater than 1.25 nm, hardness can be predicted using a simple proposed model; (2) dislocation density ρ experiences significant variations, leveling off at an indentation depth around 1.0 nm; (3) when TB spacing d exceeds 1.25 nm, plastic deformation is dominated by dislocation nucleation, slips, and boundary interactions, while smaller spacings lead to TB migration and the presence of independent dislocation loops, giving rise to force fluctuations along indentation.

In this paper, two different methods for calculating the conservation laws are used, these are the direct construction of conservation laws and the conservation theorem proposed by Ibragimov. Using these two methods, we obtain the conservation laws of the Gardner equation, Landau–Ginzburg–Higgs equation and Hirota–Satsuma equation, respectively.