International Journal of Modern Physics B

Low-dimensional complex oxides offer new opportunities for small-scale electronic devices where diverse spin, charge and orbital correlations can be suitably adapted by manipulating many-body interactions, geometries, disorder, fields, strain, etc. Therefore, oxides may be viewed as one of the promising candidates for replacing semiconductors in future devices. Maintaining coherence and control in a qubit is an important necessity for quantum computation. In this review, we discuss an example of oxide devices: decoherence-free oxide-based qubits. We present recent progress in demonstrating that long coherence times can be achieved at easily accessible temperatures in charge qubits of oxide double quantum dots. For treating strong coupling to the environment, we describe a nonperturbative approach that is useful for oxides. We illustrate ways to enhance the coherence times: increasing the electron–phonon coupling, detuning the dots to a fraction of the optical phonon energy, decreasing the temperature or reducing the adiabaticity.

A study of electrical breakdown across bias and top electrodes and its effect on the reliability of RF MEMS ohmic switches is presented. Tests under two situations were applied to study the electrical breakdown characteristic between bias and top electrodes, the first is the 10 h continuous stress under on state and the second is the voltage sweep from 0 V to 80 V. During the test, the switch ohmic contact resistance and current across bias and top electrodes were monitored simultaneously. Current across bias and top electrodes is observed in both of the two situations. Further analysis by FIB and SEM shows the breakdown damage on the surface of the bias electrode, which leads to the pull-in voltage shift of the RF MEMS ohmic switches.

Based on the previous works [J. X. Tian, Y. X. Gui and A. Mulero, J. Phys. Chem. B 114, 13399 (2010); Phys. Chem. Chem. Phys. 12, 13597 (2010)], we constructed a new equation of state for the hard tetrahedron (HTH) fluid at stable state by using the recently published Monte Carlo simulation data [J. Kolafa and S. Labík, Mol. Phys. 113, 1119 (2015)]. It can reproduce the correct virial coefficients upto nine, which is the known highest order of virial coefficient for HTH fluid. It also describes the simulation data of the compressibility factor versus the packing fraction at stable state with high accuracy.

The xLi[Li${}_{1/3}$Mn${}_{2/3}$]O${}_2\cdot$(1−x)Li[Ni${}_{1/3}$Mn${}_{1/3}$Co${}_{1/3}$]O₂ was prepared by coprecipitation method in this paper. Co(NO₃)₂, NiCO${}_3\cdot 2$Ni(OH)${}_2\cdot 4$H₂O, LiOH⋅H₂O and MnSO${}_4\cdot$H₂O were used as the sources of cobalt, nickel, lithium and manganese. In the process of calcining and sintering, the temperature and time of the material were studied. The optimum conditions for the coprecipitation method synthesis were determined: precursor was pre-sintered at 500${}^{\circ }$C for 5 h, then the precursor was successively sintered at 850${}^{\circ }$C for 9 h to get the final product. The results of XRD and SEM showed that the composite particles and crystal structure of the particles exhibited basic integrity and high degree of crystallinity with $\alpha$-NaFeO₂-type structure. The first charging and discharging capacities were 183.14 mA⋅h⋅g${}^{-1}$ and 171.11 mA⋅h⋅g${}^{-1}$ at 0.1 C with a discharge efficiency of 93%. The capacity retention rate was 95% over 20 cycles. It had a good electrochemical cycling performance.

Numerical simulations of the sound transmission loss (STL) of a double-panel structure (DPS) with sonic crystal (SC) comprised of distributed local resonators are presented. The Local Resonant Sonic Crystal (LRSC) consists of “C”-shaped Helmholtz resonator columns with different resonant frequencies. The finite element method is used to calculate the STL of such a DPS. First, the STLs of LRSC in free space and the DPS with LRSC are calculated and compared. It is shown that the sound insulations of the local resonators inserted in the double panel are higher than that in free space for the same size of the SCs and the same number of columns. Next, STL of the DPS in which the SC composed of three columns of local resonators having the same outer and inner diameters but different slot widths are calculated, and a reasonable arrangement order is determined. Finally, the soundproofing performances of DPS with distributed LRSC are compared with the case of insertion of general cylindrical SC for SC embedded in glass wool and not. The results show that the sound insulation of the DPS can be significantly improved in the low frequency range while reducing the total mass without increasing the thickness.

The main objective of this paper is to introduce a new quantum mechanism of condensates and superconductivity based on a new interpretation of quantum mechanical wavefunctions, and on recent developments in quantum physics and statistical physics. First, we postulate that the wavefunction $\psi =\left|\psi \right|$e${}^{i\phi }$ is the common wavefunction for all particles in the same class determined by the external potential V(x), $|\psi$(x)${|}^2$ represents the distribution density of the particles, and $\frac{\hslash }{m}\nabla \phi$ is the velocity field of the particles. Although the new interpretation does not alter the basic theories of quantum mechanics, it is an entirely different interpretation from the classical Bohr interpretation, removes all absurdities and offers new insights for quantum physics and for condensed matter physics. Second, we show that the key for condensation of bosonic particles is that their interaction is sufficiently weak to ensure that a large collection of boson particles are in a state governed by the same condensation wavefunction field $\psi$ under the same bounding potential V. For superconductivity, the formation of superconductivity comes down to conditions for the formation of electron pairs, and for the electron pairs to share a common wavefunction. Thanks to the recently developed principle of interaction dynamics (PID) interaction potential of electrons and the average-energy level formula of temperature, these conditions for superconductivity are explicitly derived. Furthermore, we obtain both microscopic and macroscopic formulas for the critical temperature. The field and topological phase transition equations for condensates are also derived.

The Stirling’s estimation to $ln$(N!) is typically introduced to students as a step in the derivation of the statistical expression for the heat capacity. However, naïve application of this estimation leads to wrong conclusions. In this paper, firstly, the heat capacity of some semiconductor compounds was calculated using exponential Boltzmann distribution and compared with experimental data. It has shown a disagreement between experimental results and those calculated. Secondly, by applying the more exact Stirling formula, an analytical formulation of Boltzmann statistics using Lambert W function is shown to be a very good model and proves an excellent agreement between calculated and experimental data for heat capacity over the entire temperature range.

First principles investigations of the electronic, optical and thermoelectric performance of RbZn${}_{1-x}$Ni${}_x$F₃ (x = 0, 0.25, 0.5, 0.75 and 1) alloys are calculated using spin polarized full-potential linear augmented plane wave method, as implemented in Wien2k code. These alloys are found to be stable, ductile and can be formed with ferromagnetic character. RbZn${}_{1-x}$Ni${}_x$F₃ are found to be insulator alloys with bandgap energy of range 7.02–5.14 eV using the modified Becke–Johnson functional. This gap is decreasing with increasing the Ni concentration in the unit cell. The optical parameters are calculated in the energy range upto 35 eV. The calculated static refractive index values are found directly proportional with the higher concentration of Ni atoms in the alloys. The transport coefficients are calculated using BoltzTrap code. The hole assumes the main charge carriers of the present alloys with p-type-doping for RbZnF₃ alloy and n-type-doping for RbZn${}_{1-x}$Ni${}_x$F₃. The calculated optical and transport coefficient values show promising optoelectronic and thermoelectric applications of the studied alloys.

Magnetic ordering in a mixed domain structure composed of a stripe domain and asymmetrically localized magnetic impurity inside the stripe domain was investigated. The analytical expression for domain walls deformation mediated by the influence of the magnetostatic stray field of the asymmetrically localized magnetic impurity was obtained. The calculations were done for the magnetic film with parameters which are typical for films used in magnetic memory. Experimental implementation of the mixed domain structure composed of the stripe domain and asymmetrically localized magnetic impurity inside the stripe domain was done in (BiLu)₃(FeGa)₅O₁₂ film. Obtained analytical solution for the shape of stripe domain walls distortion is in excellent agreement with the experimental results.

Phosphorene is a new two-dimensional material that has great potentials in Nano electronic application, so it has attracted more researchers’ attention nowadays. Indeed, phosphorene is an interesting material in gas sensing, due to its high surface-to-volume ratio and its carrier mobility. Many studies have been reported on phosphorene gas sensing, but there is not enough study on analytical modeling of phosphorene gas sensing properties. In this research, by adopting data from experimental NO₂-based gas sensor, an analytical model of the phosphorene gas sensing behavior is presented. Then, the experimental results of NO₂ gas sensing are compared with the proposed model and acceptable agreement is reported. This new model is adapted to predict phosphorene gas sensing performance in higher NO₂ gas concentrations, which demonstrates, linear relation is established in higher concentrations same as lower ppb NO₂ gas concentration. So, we have predicted the result of NO₂ gas sensing for higher concentration based on experimental sensing.

In this paper, we investigate the valley-dependent electron transport in graphene modulated by a strained barrier which can induce a large valley polarization in this structure. Our results show that the valley polarization can be easily controlled by changing the strength, the position and/or the width of the strained barrier. This remarkable feature could be used in the fabrication of valleytronic devices based on graphene controlled by the strained barrier.

Girolami and coworkers have proposed measures of quantum correlations and weaving [Girolami et al., Phys. Rev. Lett. 119, 140505 (2017)]. This work derives the analytic time-evolution of such measures and weaving for two kinds of initial states in three qubits under an amplitude-damping and a dephasing noisy environment. It is shown that the 2-partite correlation is forever frozen, which is dependent on an initial state and the property of noise.

A self-consistent model of thorium dioxide and its dilute alloys with cerium is developed. Thermal and elastic properties of ThO₂ and several variations of Ce${}_{0.05}$Th${}_{0.95}$O₂ synthesized by various techniques (powder processing and pelletization (POP) and coated agglomerate pelletization process (CAP) and using two different atmospheres, i.e., air or Ar$+$H₂ mixture) are simulated. The influence of porosity on degree of phonon anharmonicity and on the lattice properties (in particular, thermal conductivity) of the considered systems is analyzed.

In this paper, we study a 6-field integrable lattice system, which, in some special cases, can be reduced to the self-dual network equation, the discrete second-order nonlinear Schrödinger equation and the relativistic Volterra lattice equation. With the help of the Lax pair, we construct infinitely many conservation laws and a new Darboux transformation for system. Exact solutions resulting from the obtained Darboux transformation are presented by using a given seed solution. Further, we generate the soliton solutions and plot the figures of one-soliton solutions with properly parameters.