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<jats:p>As one of important members of refractory materials, tungsten phosphide (WP) holds great potential for fundamental study and industrial applications in many fields of science and technology, due to its excellent properties such as superconductivity and as-predicted topological band structure. However, synthesis of high-quality WP crystals is still a challenge by using tradition synthetic methods, because the synthesis temperature for growing its large crystals is very stringently required to be as high as 3000 °C, which is far beyond the temperature capability of most laboratory-based devices for crystal growth. In addition, high temperature often induces the decomposition of metal phosphides, leading to off-stoichiometric samples based on which the materials’ intrinsic properties cannot be explored. In this work, we report a high-pressure synthesis of single-crystal WP through a direct crystallization from cooling the congruent W–P melts at 5 GPa and ∼ 3200 °C. In combination of x-ray diffraction, electron microscope, and thermal analysis, the crystal structure, morphology, and stability of recovered sample are well investigated. The final product is phase-pure and nearly stoichiometric WP in a single-crystal form with a large grain size, in excess of one millimeter, thus making it feasible to implement most experimental measurements, especially, for the case where a large crystal is required. Success in synthesis of high-quality WP crystals at high pressure can offer great opportunities for determining their intrinsic properties and also making more efforts to study the family of transition-metal phosphides.</jats:p>

<jats:p>A sequential of concepts developed in the last decade has enabled a resolution to multiple anomalies of water ice and its low-dimensionality, particularly. Developed concepts include the coupled hydrogen bond (O:H–O) oscillator pair, segmental specific heat, three-body coupling potentials, quasisolidity, and supersolidity. Resolved anomalies include ice buoyancy, ice slipperiness, water skin toughness, supercooling and superheating at the nanoscale, etc. Evidence shows consistently that molecular undercoordination shortens the H–O bond and stiffens its phonon while undercoordination does the O:H nonbond contrastingly associated with strong lone pair “:” polarization, which endows the low-dimensional water ice with supersolidity. The supersolid phase is hydrophobic, less dense, viscoelastic, thermally more diffusive, and stable, having longer electron and phonon lifetime. The equal number of lone pairs and protons reserves the configuration and orientation of the coupled O:H–O bonds and restricts molecular rotation and proton hopping, which entitles water the simplest, ordered, tetrahedrally-coordinated, fluctuating molecular crystal covered with a supersolid skin. The O:H–O segmental cooperativity and specific-heat disparity form the soul dictate the extraordinary adaptivity, reactivity, recoverability, and sensitivity of water ice when subjecting to physical perturbation. It is recommended that the premise of “hydrogen bonding and electronic dynamics” would deepen the insight into the core physics and chemistry of water ice.</jats:p>

<jats:p>Gamma-ray (<jats:italic>γ</jats:italic>-ray) radiation for silicon single photon avalanche diodes (Si SPADs) is evaluated, with total dose of 100 krad(Si) and dose rate of 50 rad(Si)/s by using <jats:sup>60</jats:sup>Co as the <jats:italic>γ</jats:italic>-ray radiation source. The breakdown voltage, photocurrent, and gain have no obvious change after the radiation. However, both the leakage current and dark count rate increase by about one order of magnitude above the values before the radiation. Temperature-dependent current–voltage measurement results indicate that the traps caused by radiation function as generation and recombination centers. Both leakage current and dark count rate can be almost recovered after annealing at 200 °C for about 2 hours, which verifies the radiation damage mechanics.</jats:p>

<jats:p>To suppress the electric field crowding at sidewall and improve the detection sensitivity of the AlGaN separate absorption and multiplication (SAM) avalanche photodiodes (APDs), we propose the new AlGaN APDs structure combining a large-area mesa with a field plate (FP). The simulated results show that the proposed AlGaN APDs exhibit a significant increase in avalanche gain, about two orders of magnitude, compared to their counterparts without FP structure, which is attributed to the suppression of electric field crowding at sidewall of multiplication layer and the reduction of the maximum electric field at the p-type GaN sidewall in p–n depletion region. Meanwhile, the APDs can produce an obviously enhanced photocurrent due to the increase in cross sectional area of multiplication region.</jats:p>

<jats:p>Very recently, experimental evidence showed that the hydrogen is retained in dithiol-terminated single-molecule junction under the widely adopted preparation conditions, which is in contrast to the accepted view [<jats:italic>Nat. Chem.</jats:italic> <jats:bold>11</jats:bold> 351 (2019)]. However, the hydrogen is generally assumed to be lost in the previous physical models of single-molecule junctions. Whether the retention of the hydrogen at the gold—sulfur interface exerts a significant effect on the theoretical prediction of spin transport properties is an open question. Therefore, here in this paper we carry out a comparative study of spin transport in <jats:italic>M</jats:italic>-tetraphenylporphyrin-based (<jats:italic>M</jats:italic> = V, Cr, Mn, Fe, and Co; <jats:italic>M</jats:italic>-TPP) single-molecule junction through Au–SR and Au–S(H)R bondings. The results show that the hydrogen at the gold–sulfur interface may dramatically affect the spin-filtering efficiency of <jats:italic>M</jats:italic>-TPP-based single-molecule junction, depending on the type of transition metal ions embedded into porphyrin ring. Moreover, we find that for the Co-TPP-based molecular junction, the hydrogen at the gold–sulfur interface has no obvious effect on transmission at the Fermi level, but it has a significant effect on the spin-dependent transmission dip induced by the quantum interference on the occupied side. Thus the fate of hydrogen should be concerned in the physical model according to the actual preparation condition, which is important for our fundamental understanding of spin transport in the single-molecule junctions. Our work also provides guidance in how to experimentally identify the nature of gold–sulfur interface in the single-molecule junction with spin-polarized transport.</jats:p>

<jats:p>We report a p24 (HIV disease biomarker) detection assay using an MgO-based magnetic tunnel junction (MTJ) sensor and 20-nm magnetic nanoparticles. The MTJ array sensor with sensing area of 890 × 890 μm<jats:sup>2</jats:sup> possessing a sensitivity of 1.39 %/Oe was used to detect p24 antigens. It is demonstrated that the p24 antigens could be detected at a concentration of 0.01 μg/ml. The development of bio-detection systems based on magnetic tunnel junction sensors with high-sensitivity will greatly benefit the early diagnosis of HIV.</jats:p>

<jats:p>The dynamics of zero-range processes on complex networks is expected to be influenced by the topological structure of underlying networks. A real space complete condensation phase transition in the stationary state may occur. We study the finite density effects of the condensation transition in both the stationary and dynamical zero-range processes on scale-free networks. By means of grand canonical ensemble method, we predict analytically the scaling laws of the average occupation number with respect to the finite density for the steady state. We further explore the relaxation dynamics of the condensation phase transition. By applying the hierarchical evolution and scaling ansatz, a scaling law for the relaxation dynamics is predicted. Monte Carlo simulations are performed and the predicted density scaling laws are nicely validated.</jats:p>

<jats:p>We propose a new heterogeneous parallel strategy for the density matrix renormalization group (DMRG) method in the hybrid architecture with both central processing unit (CPU) and graphics processing unit (GPU). Focusing on the two most time-consuming sections in the finite DMRG sweeps, i.e., the diagonalization of superblock and the truncation of subblock, we optimize our previous hybrid algorithm to achieve better performance. For the former, we adopt OpenMP application programming interface on CPU and use our own subroutines with higher bandwidth on GPU. For the later, we use GPU to accelerate matrix and vector operations involving the reduced density matrix. Applying the parallel scheme to the Hubbard model with next-nearest hopping on the 4-leg ladder, we compute the ground state of the system and obtain the charge stripe pattern which is usually observed in high temperature superconductors. Based on simulations with different numbers of DMRG kept states, we show significant performance improvement and computational time reduction with the optimized parallel algorithm. Our hybrid parallel strategy with superiority in solving the ground state of quasi-two dimensional lattices is also expected to be useful for other DMRG applications with large numbers of kept states, e.g., the time dependent DMRG algorithms.</jats:p>

<jats:p>Coriolis effect is an important error source in the weak equivalence principle (WEP) test using atom interferometer. In this paper, the problem of Coriolis error in WEP test is studied theoretically and experimentally. In theoretical simulation, the Coriolis effect is analyzed by establishing an error model. The measurement errors of Eötvös coefficient (<jats:italic>η</jats:italic>) in WEP test related to experimental parameters, such as horizontal-velocity difference and horizontal-position difference of atomic clouds, horizontal-position difference of detectors, and rotation compensation of Raman laser’s mirror are calculated. In experimental investigation, the position difference between <jats:sup>85</jats:sup>Rb and <jats:sup>87</jats:sup>Rb atomic clouds is reduced to 0.1 mm by optimizing the experimental parameters, an alternating detection method is used to suppress the error caused by detection position difference, thus the Coriolis error related to the atomic clouds and detectors is reduced to 1.1× 10<jats:sup>−9</jats:sup>. This Coriolis error is further corrected by compensating the rotation of Raman laser’s mirror, and the total uncertainty of <jats:italic>η</jats:italic> measurement related to the Coriolis effect is reduced as <jats:italic>δη</jats:italic> = 4.4 × 10<jats:sup>−11</jats:sup>.</jats:p>

<jats:p>Nematic phase intertwines closely with high-<jats:italic>T</jats:italic> <jats:sub>c</jats:sub> superconductivity in iron-based superconductors. Its mechanism, which is closely related to the pairing mechanism of superconductivity, still remains controversial. Comprehensive characterization of the electronic state reconstruction in the nematic phase is thus crucial. However, most experiments focus only on the reconstruction of band dispersions. Another important characteristic of electronic state, the spectral weight, has not been studied in details so far. Here, we studied the spectral weight transfer in the nematic phase of FeSe<jats:sub>0.9</jats:sub>S<jats:sub>0.1</jats:sub> using angle-resolved photoemission spectroscopy and <jats:italic>in-situ</jats:italic> detwinning technique. There are two elliptical electron pockets overlapping with each other orthogonally at the Brillouin zone corner. We found that, upon cooling, one electron pocket loses spectral weight and fades away, while the other electron pocket gains spectral weight and becomes pronounced. Our results show that the symmetry breaking of the electronic state is manifested by not only the anisotropic band dispersion but also the band-selective modulation of the spectral weight. Our observation completes our understanding of the nematic electronic state, and put strong constraints on the theoretical models. It further provides crucial clues to understand the gap anisotropy and orbital-selective pairing in iron-selenide superconductors.</jats:p>