Evidence of unconventional pairing in the quasi two-dimensional CuIr${}_2$Te${}_4$ superconductor

Abstract

The CuIr${}_{2-x}$Ru${}_x$Te${}_4$ superconductors (with a $T_c$ around 2.8 K) can host charge-density waves, whose onset and interplay with superconductivity are not well known at a microscopic level. Here, we report a comprehensive study of the $x$ = 0 and 0.05 cases, whose superconductivity was characterized via electrical-resistivity-, magnetization-, and heat-capacity measurements, while their microscopic superconducting properties were studied via muon-spin rotation and relaxation ($\mu$SR). In CuIr${}_{2-x}$Ru${}_x$Te${}_4$, both the temperature-dependent electronic specific heat and the superfluid density (determined via transverse-field $\mu$SR) are best described by a two-gap (s+d)-wave model, comprising a nodeless gap and a gap with nodes. The multigap superconductivity is also supported by the temperature dependence of the upper critical field $H_{c2}(T)$. However, under applied pressure, a charge-density-wave order starts to develop and, as a consequence, the superconductivity of CuIr${}_2$Te${}_4$ achieves a more conventional s-wave character. From a series of experiments, we provide ample evidence that the CuIr${}_{2-x}$Ru${}_x$Te${}_4$ family belongs to the rare cases, where an unconventional superconducting pairing is found near a charge-density-wave quantum critical point.

arXiv comment10 pages, 12 figures

References in corpus (27)

• Nematic order in iron superconductors - who is in the driver's seat?
• Superconductivity in CuxBi2Se3 and its implications for pairing in the undoped topological insulator
• Superconductivity in Cu_xTiSe_2
• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Discovery of unconventional chiral charge order in kagome superconductor KV3Sb5
• Topological Superconductivity in CuxBi2Se3
• musrfit: A free platform-independent framework for muSR data analysis
• Spin-polarized muons in condensed matter physics
• Phenomenological two-gap model for the specific heat of MgB_2
• Properties of the Ideal Ginzburg-Landau Vortex Lattice
• Pressure-induced and Composition-induced Structural Quantum Phase Transition in the Cubic Superconductor (Sr/Ca)_3Ir_4Sn_{13}
• Using controlled disorder to probe the interplay between charge order and superconductivity in NbSe2
• Comparison of different methods for analyzing $\mu$SR line shapes in the vortex state of type-II superconductors
• Simultaneous Nodal Superconductivity and Time-Reversal Symmetry Breaking in the Noncentrosymmetric Superconductor CaPtAs
• Evidence of Nodal Line in the Superconducting Gap Symmetry of Noncentrosymmetric ThCoC${}_2$
• Nodeless superconductivity and preserved time-reversal symmetry in the noncentrosymmetric Mo3P superconductor
• Enhanced $T_c$ and multiband superconductivity in the fully-gapped ReBe${}_{22}$ superconductor
• Strong enhancement of conventional superconductivity near a quantum critical point of (Ca,Sr)_3Ir_4Sn_13
• Two-band superconductivity featuring different anisotropies in the ternary iron silicide Lu${}_2$Fe${}_3$Si${}_5$
• Superconductivity in the Cu(Ir1-xPtx)2Se4 Spinel
• Superconductivity in the Ru-Doped CuIr2Te4 Telluride Chalcogenide
• Charge-Stripe Order and Superconductivity in $\mathrm{I}{\mathrm{r}}_{1-\mathrm{x}}\mathrm{P}{\mathrm{t}}_{\mathrm{x}}\mathrm{T}{\mathrm{e}}_2$
• Pauli-limit violation in lanthanide infinite-layer nickelate superconductors
• CuIr2Te4: A Quasi-Two-Dimensional Ternary Telluride Chalcogenide Superconductor
• Anomalous Charge Density Wave State Evolution and Dome-like Superconductivity in CuIr2Te4-xSex Chalcogenides
• Superconducting dome associated with the suppression and re-emergence of charge density wave states upon sulfur substitution in CuIr2Te4 chalcogenides
• Superconductivity in CuIr2-xAlxTe4 telluride chalcogenides