Superconductivity in Mo-P compounds under pressure and in double-Weyl semimetal Hex-MoP2.

Based on first-principles calculations, we predict five global stable molybdenum phosphorus compounds in the pressure range of 0-300 GPa. All of them display superconductivity with different transition temperatures. Meanwhile, we find that a metastable crystal hex-MoP2, crystallized in a noncentrosymmetric structure, is a double-Weyl semimetal and the Weyl point is in the H-K path. The long Fermi arcs and the topological surface states, which can be observed by angle-resolved photoemission spectroscopy, emerge at the (100) surface below the Fermi level. Furthermore, we find that the superconductivity in hex-MoP2 can be enhanced by carrier doping. Due to the breaking of inversion symmetry, the unconventional spin-triplet pairing coexists with spin-singlet pairing in channel . Based on our theoretical model, there are the superconducting band gaps in both pairings. Our work provides a new platform of hex-MoP2 for studying both topological double-Weyl semimetal and superconductivity.

Inelastic Electron Tunneling in 2H-Ta_{x}Nb_{1-x}Se_{2} Evidenced by Scanning Tunneling Spectroscopy.

We report a detailed study of tunneling spectra measured on 2H-Ta_{x}Nb_{1-x}Se_{2} (x=0∼0.1) single crystals using a low-temperature scanning tunneling microscope. The prominent gaplike feature, which has not been understood for a long time, was found to be accompanied by some "in-gap" fine structures. By investigating the second-derivative spectra and their temperature and magnetic field dependencies, we were able to prove that inelastic electron tunneling is the origin of these features and obtain the Eliashberg function of 2H-Ta_{x}Nb_{1-x}Se_{2} at an atomic scale, providing a potential way to study the local Eliashberg function and the phonon spectra of the related transition-metal dichalcogenides.

[Biodegradation of LAS in the anaerobic water of a representative inlet of Lake Dianchi].

Biodegradation and degradation kinetics of anion-surfactant (LAS) in the anaerobic water of a representative inlet (Haihe River) of Lake Dianchi under different incubation conditions were studied by the 'river die-away' test method. The influences of temperature, pH, initial concentration of LAS, aeration condition and added nutrients (NH4Cl or NaH2PO4) on the biodegradation of LAS in the water were investigated. The results demonstrate that LAS can be biodegraded by microorganisms in the water and that the percentage of degradation of LAS was more than 95% after 26 d. The biodegradation of LAS fit the second kinetic model. Incubation temperature, initial concentration of LAS, aeration and added nutrients (NH4Cl or NaH2PO4) can all affect the biodegradation of LAS. When the incubation temperature increased from 10 degrees C to 25 degrees C, the biodegradation rate (p) of LAS increased from 0.21 d(-1) to 0.90 d(-1). The LAS degradation rate increased from 0.72 d(-1) under anaerobic condition to 1.97 d(-1) under continuous aeration condition. The increased initial concentrations of LAS lead to decrease of the biodegradation rate. NaH2PO4 accelerated the degradation of LAS but added NH4Cl instead inhibited degradation. In our experiment, pH value (7.05-9.44) had little influence on the biodegradation of LAS.