Effect of Selenium doping on the superconductivity of Nb${}_2$Pd(S${}_{1-x}$Se${}_x$)${}_5$

Abstract

We study the isovalent substitution effect by partially introducing Se on S site in the newly discovered superconductor Nb${}_2$PdS${}_5$ ($T_c\sim$6 K) whose upper critical field is found to be far above its Pauli paramagnetic limit. In this Nb${}_2$Pd(S${}_{1-x}$Se${}_x$)${}_5$ (0$\le$$x$$\le$0.8) system, superconductivity is systematically suppressed by the Se concentration and ultimately disappears when $x\ge$ 0.5, after which a semiconducting-like ground state emerges. In spite of the considerably reduced $T_c$ with Se doping, the ratio of the upper critical field $H_{c2}$ to $T_c$, remains unaffected. Moreover, the size of the heat capacity jump at $T_c$ is smaller than that expected for a BCS superconductor, implying that a strong-coupling theory cannot be the origin of this large upper critical field. In addition, the low-lying quasiparticle excitations are consistent with a nodeless gap opening over the Fermi surface. These results combined impose severe constraints on any theory of exotic superconductivity in this system.

5 pages, 4 figures

References in corpus (9)

• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• Nearly Isotropic superconductivity in (Ba,K)Fe2As2
• Hidden quasi one-dimensional superconductivity in Sr${}_2$RuO${}_4$
• Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2
• Specific heat evidence for two-gap superconductivity in ternary-iron silicide Lu${}_2$Fe${}_3$Si${}_5$
• Multiband effects on beta-FeSe single crystals
• Superconductivity with extremely large upper critical fields in Nb2Pd0.81S5
• Two-band superconductivity featuring different anisotropies in the ternary iron silicide Lu${}_2$Fe${}_3$Si${}_5$
• Anomalous metallic state and anisotropic multiband superconductivity in Nb3Pd0.7Se7

Cited by in corpus (18)

• Superconductivity at 6 K and the violation of Pauli limit in Ta2PdxS5
• Superconductivity in a Layered Ta4Pd3Te16 with PdTe2 Chains
• Superconductivity and Fermi Surface Nesting in the Candidate Dirac Semimetal NbC
• Enhanced Upper Critical Fields in a New Quasi-one-dimensional Superconductor Nb2PdxSe5
• Robust superconductivity with large upper critical field in Nb2PdS5
• Controllable spin-orbit coupling and its influence on the upper critical field in the chemically doped quasi-one-dimensional Nb${}_2$PdS${}_5$ superconductor
• Electronic phase diagram in the new BiS2-based Sr1-xLaxFBiS2 system
• Pressure-induced superconductivity in quasi-one-dimensional semimetal ${\mathrm{Ta}}_2{\mathrm{PdSe}}_6$
• Upward curvature of the upper critical field and the V-shaped pressure dependence of $T_c$ in the noncentrosymmetric superconductor PbTaSe${}_2$
• Superconductivity at 2.5 K in new transition-metal chalcogenide Ta2PdSe5
• Nodeless superconductivity in quasi-one-dimensional Nb2PdS5: A muSR study
• Time-reversal-symmetry Breaking in the Superconducting State of ScS
• Anomalous Charge Density Wave State Evolution and Dome-like Superconductivity in CuIr2Te4-xSex Chalcogenides
• Enhanced superconductivity in hole-doped Nb${}_2$PdS${}_5$
• Multiband Semimetallic Electronic Structure of Superconducting Ta2PdSe5
• Single gap s-wave superconductivity in Nb2PdS5
• Evidence for nodal superconductivity in a layered compound Ta${}_4$Pd${}_3$Te${}_{16}$
• Superconductivity in centrosymmetric topological superconductor candidate TaC