MXenes have potential applications for adsorbing radioactive elements and protecting surfaces of radioactive materials. Keeping integrity is important for practical applications. Thus, an efficient way for detecting h...
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Pursuing higher-temperature superconductors under ambient pressure continues to be a prominent topic in materials discovery. Isomorphic structures like MgB2 exhibit potential for conventional BCS-type superconductivit...
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Pursuing higher-temperature superconductors under ambient pressure continues to be a prominent topic in materials discovery. Isomorphic structures like MgB2 exhibit potential for conventional BCS-type superconductivity, but their transition temperatures Tc have remained below 100 K based on both experimental findings and theoretical predictions. In this study, two two-dimensional (2D) superconductors with sandwich structures, KB2C2, featuring BC layers in AA and AB stacking configurations, are designed, whose Tc can exceed 112 K. The analyses suggest that electrons in σ-state covalent bonds and high-frequency E phonon modes dominated by the in-plane vibrations of B and C atoms are predominately responsible for electron-phonon coupling (EPC). An exciting robust three-gap superconducting nature stems from the strong and evident three-region distribution characteristic of electronic EPC parameters λkel. When biaxial tensile strain (BTS) is applied, their Tc are boosted above 153 K. The increase in Tc originates from the softening of optical E phonon modes around the Γ point and acoustic modes around the Q point, rather than an increase of electrons at the Fermi level EF, as observed in other similar systems. Thus, phonons play a more beneficial role in the EPC of BTS cases, highlighting its significance as a medium in BCS superconductors. Moreover, we find KB2C2 exhibits interesting topological properties, spin antivortex, and Ising-type spin splitting. It is significantly meaningful to report that the coexistence of nontrivial topology and superconductivity with such a high Tc. Therefore, KB2C2 may offer promising sandwich structures to explore higher-Tc two-dimensional superconductors, alongside present potential avenues for investigating fundamental quantum physics.
The stopping power of warm dense plasmas for electrons is a critical aspect in the study of hot electron transport. An externally applied strong magnetic field can significantly influence electron transport behavior d...
The stopping power of warm dense plasmas for electrons is a critical aspect in the study of hot electron transport. An externally applied strong magnetic field can significantly influence electron transport behavior due to various factors. However, the impact of external magnetic fields on the motion of incident particles is often overlooked. Through molecular dynamics simulations using the electron force field (eFF) method, this study investigates the stopping process of individual hot electrons in warm dense deuterium plasma under an applied longitudinal magnetic field. Results show that, at typical laboratory magnetic field intensities, the magnetic field significantly alters electron trajectories without notable effects on average stopping power, trajectory length, or scattering angle. Even with increased magnetic field intensity beyond 500 kT, it doesn’t affect the total kinetic energy loss of incident electrons but reduces stopping power by compressing the scattering angle distribution width. Due to the increase in the scattering angle distribution width with intensified fluctuations in high-temperature targets, the impact of the additional magnetic field on stopping power becomes more pronounced with an increase in target temperature.
We investigate the long time existence of strong solutions to the initial value problem for the three-dimensional non-isentropic compressible Navier-Stokes-Korteweg system. Under the conditions of slight density and t...
We investigate the long time existence of strong solutions to the initial value problem for the three-dimensional non-isentropic compressible Navier-Stokes-Korteweg system. Under the conditions of slight density and temperature variations, we verify that the full compressible Navier-Stokes-Korteweg equations admit a unique strong solution as long as the solution of the limiting system exists, when the Mach number is sufficiently small. Furthermore, we deduce the uniform convergence of strong solutions for the compressible system toward those for the corresponding incompressible system on the time interval in which the solution exists.
The Monte Carlo simulation of large-scale neutron transport problems has always faced the problem of slow computation. In order to fully exploit the acceleration advantage of heterogeneous parallelism on the Monte Car...
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We study the quantum transport in double quantum dots (DQD) sandwiched between surfaces of topological insulator (TI) Bi2Te3, which possess strong spin-orbit coupling (SOC) and dC3v double group symmetry. Different fr...
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We study the quantum transport in double quantum dots (DQD) sandwiched between surfaces of topological insulator (TI) Bi2Te3, which possess strong spin-orbit coupling (SOC) and dC3v double group symmetry. Different from the spin-conserved case with two-dimensional electron gas (2DEG) electrodes, the conductance displays a universal scaling relation for different Fermi energy associated with the topological nature/linear dispersion of topological surface states. The interplay between direct interdot tunneling and surface state mediated interaction leads to tunable Dicke and Fano effects with changing the interdot distance. We propose nano-rulers with different measurement range and resolution based on the Fano q-factor. Furthermore, when applying an in-plane Zeeman field, a crossover from a double-peak shape to a quad-peak shape in conductance curve appears. Moreover, the rotational symmetry of the system could also be revealed from the conductance pattern. Our findings contribute to a better understanding of the quantum transport in the presence of electrode's SOC topological states.
The influences of external strain on optical properties of defective functionalized MXenes Ti3C2Tx (T = F, O, OH) are systematically studied by first-principles calculations. We find that biaxial strains significantly...
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Early hot electron can preheat the pellet fuel and thus lead to lower implosion performance. The properties of hot electrons in early stage of implosion experiments in Shenguang-100 kJ laser facility were investigated...
Early hot electron can preheat the pellet fuel and thus lead to lower implosion performance. The properties of hot electrons in early stage of implosion experiments in Shenguang-100 kJ laser facility were investigated. It was shown that both the temperature and the energy of early hot electrons were very low. The upper limit of the temperature and the energy of early hot electrons in our experiments were only 7.7 keV and 0.35 J, respectively. Besides, the generation mechanisms of early hot electrons were also different from NIF experiments according to the results of the hard X-ray imager (HXI). In NIF experiments, two-plasmon decay and multi-beam stimulated Raman scattering (SRS) were dominate mechanisms that generate early hot electrons. However, SRS of the outer beams was our dominant mechanism. Spectrum of the scattered light of SRS was obtained by radiative hydrodynamic and ray-tracing simulations. The result showed that the spectrum was peaked at $$\lambda _\textrm{s}=482\,\hbox {nm}$$ , which meant hot electrons with the temperature near 7keV can be generated. And from the result of HXI, hot electrons deposited onto the pellet were estimated to less than $$6.8\times 10^{-3}$$ J. Deeper analysis showed that, in the beam overlapping region, the plasma density was unsuitable for multi-beam SRS, so no hot electrons with larger temperature were generated.
We study the existence and zero viscous limit of smooth solutions to steady compressible Navier-Stokes equations near plane shear flow between two moving parallel walls. Under the assumption 0 0 = (µ(x2), 0), the...
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We conducted a study on the electron stopping power of protons in aluminum at finite electron temperatures, utilizing time-dependent density functional theory nonadiabatically coupled with molecular dynamics. Our inve...
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We conducted a study on the electron stopping power of protons in aluminum at finite electron temperatures, utilizing time-dependent density functional theory nonadiabatically coupled with molecular dynamics. Our investigation focused on protons with initial velocities ranging from 0.1 to 1.0 a.u., providing a wealth of detailed information on the electronic states involved in the stopping process, with exceptional spatial and temporal resolution. Our results show that the electron temperature can significantly effect the electron stopping power. A quantum-blocking mechanism based on a physical picture of electronic transitions in energy levels has been proposed for explaining the phenomenon of electron stopping power decreasing with the increase of target electron temperature.
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