Superconducting Properties and Absence of Time Reversal Symmetry Breaking in the Noncentrosymmetric Superconducting Compounds Ta_(x)Re_(1-x)(0.1≤x≤0.25)

Unconventional superconductivity,in particular,in noncentrosymmetric systems,has been a long-sought topic in condensed matter physics.Recently,Re-based superconductors have attracted great attention owing to the potential time-reversal symmetry breaking in their superconducting states.We report the superconducting properties of noncentrosymmetric compounds Ta_(x)Re_(1-x) with 0.1 ≤x≤0.25,and find that the superconducting transition temperature reaches a maximum of ~8 K at the optimal level x=0.15.Nevertheless,muon-spin rotation and relaxation measurements reveal no time-reversal symmetry breaking existing in its superconducting state,which is in sharp contrast to both centrosymmetric Re metal and many other noncentrosymmetric Re-based superconductors.

Anisotropic transport in a possible quasi-one-dimensional topological candidate:TaNi_(2)Te_(3)

We report on the solid-state synthesis and the strongly anisotropic transport properties of the ternary telluride TaNi_(2)Te_(3),whose three orthogonal resistivity coefficients exhibit a large ratio of 1.4:1:2294(14:1:2303) at 300 K(2 K),thereby demonstrating its quasi-one-dimensional(q1D) electronic structure.The Kohler’ s rule in different current/field configurations shows a moderate violation.Its one dimensionality manifests itself in the needle-like shape of crystal,the large anisotropic resistivity and the flat Fermi surface normal to the chain direction.Moreover,the first-principles calculations also provide evidence for the existence of the nontrivial topological carriers in this q1D system.Our calculation demonstrates that TaNi_(2)Te_(3) is a strong topological nontrivial material with topological indices(1;1 0 1) and its nontrivial topology is also evidenced from its bulk-surface correspondence.Our study may therefore offer a new platform for engineering the topologically nontrivial phase in low-dimensional materials,in analogy to the recently discovered q1D topological TaNiTe_(5).

Phase diagram and transport properties of Sb-doped Ca0.88La0.12Fe2As2 single crystals

The effects of isovalent Sb substitution on the superconducting properties of the Ca0.88La0.12Fe2（As1-ySby）2 system have been studied through electrical resistivity measure- ments. It is seen that the antiferromagnetic or structural transition is suppressed with Sb content, and a high-To superconducting phase, accompanied by a low-Tc phase, emerges at 0.02 ≤y ≤ 0.06. In this intermediate-doping regime, normal-state transport shows non-Fermi-liquid-like behaviors with nearly T-linear resistivity above the high-Tc phase. With further Sb doping, this high-Tc phase abruptly vanishes for y 〉 0.06 and the conventional Fermi liquid is restored, while the low-T,, phase remains robust against Sb inlpurities. The coincidence of the high-Tc phase and non-Fermi liquid transport behaviors in the intermediate Sb-doping regime suggests that AFM fluctuations play an important role in the observed non-Fermi liquid behaviors, which may be intimately related to the unusual nonbulk high-Tc phase in this system.