Revealing isotropic abundant low-energy excitations in UTe${}_2$ through complex microwave surface impedance

Abstract

The complex surface impedance is a well-established tool to study the super- and normal-fluid responses of superconductors. Fundamental properties of the superconductor, such as the pairing mechanism, Fermi surface, and topological properties, also influence the surface impedance. We explore the microwave surface impedance of spin-triplet UTe${}_2$ single crystals as a function of temperature using resonant cavity perturbation measurements employing a novel multi-modal analysis to gain insight into these properties. We determine a composite surface impedance of the crystal for each mode using resonance data combined with the independently measured normal state dc resistivity tensor. The normal state surface impedance reveals the weighting of current flow directions in the crystal of each resonant mode. For UTe${}_2$, we find an isotropic $\Delta \lambda (T)\sim T^{\alpha }$ power-law temperature dependence for the magnetic penetration depth for $T\le T_c/3$ with $\alpha <2$, which is inconsistent with a single pair of point nodes on the Fermi surface under weak scattering. We also find a similar power-law temperature dependence for the low-temperature surface resistance $R_s(T)\sim T^{{\alpha }_R}$ with ${\alpha }_R<2$. We observe a strong anisotropy of the residual microwave loss across these modes, with some modes showing loss below the universal line-nodal value, to those showing substantially more. We compare to predictions for topological Weyl superconductivity in the context of the observed isotropic power-laws, and anisotropy of the residual loss.

arXiv comment29 pages, 23 figures

References in corpus (31)

• Spontaneously polarized half-gapped superconductivity
• Magnetic Penetration Depth in Unconventional Superconductors
• Quasiparticle States near the Surface and the Domain Wall in a p_x\pm i p_y-Wave Superconductor
• Measurement of Resonant Frequency and Quality Factor of Microwave Resonators: Comparison of Methods
• Extreme magnetic field-boosted superconductivity
• Field-reentrant superconductivity close to a metamagnetic transition in the heavy-fermion superconductor UTe${}_2$
• Nonlocal Effects on the Magnetic Penetration Depth in d-wave Superconductors
• Probing the superconducting gap symmetry of PrOs${}_4$Sb${}_{12}$: A penetration depth study
• Point Node Gap Structure of Spin-Triplet Superconductor UTe2
• Single-component superconducting state in UTe2 at 2 K
• Anomalous normal fluid response in a chiral superconductor UTe2
• Chiral superconductivity in UTe2 probed by anisotropic low-energy excitations
• Quasi-2D Fermi surface in the anomalous superconductor UTe2
• Single-Component Superconductivity in UTe${}_2$ at Ambient Pressure
• $c$-axis transport in UTe${}_2$: Evidence of Three Dimensional Conductivity Component
• CeCoIn5 - a quantum critical superfluid
• The fate of time-reversal symmetry breaking in UTe2
• Revealing a 3D Fermi Surface Pocket and Electron-Hole Tunneling in UTe${}_2$ with Quantum Oscillations
• Fully gapped pairing state in spin-triplet superconductor UTe${}_2$
• Nodal quasiparticle dynamics in the heavy fermion superconductor CeCoIn5 revealed by precision microwave spectroscopy
• Absence of Spontaneous Magnetic Fields Due to Time-Reversal Symmetry Breaking in Bulk Superconducting UTe2
• Enhanced triplet superconductivity in next generation ultraclean UTe2
• Microscopic imaging homogeneous and single phase superfluid density in UTe${}_2$
• Molten Salt Flux Liquid Transport Method for Ultra Clean Single Crystals UTe2
• Thermodynamic transitions and topology of spin-triplet superconductivity: Application to UTe${}_2$
• Topological Anomalous Skin Effect in Weyl Superconductors
• Surface impedance anisotropy of YBa${}_2$Cu${}_3$O${}_{6.95}$ single crystals: electrodynamic basis of the measurements
• Local impedance on a rough surface of a chiral $p$-wave superconductor
• Observation of odd-parity superconductivity in UTe2
• An optical investigation of the heavy fermion normal state in superconducting UTe${}_2$
• Topological superconductivity in a spin-orbit coupled Kondo lattice

Cited by in corpus (1)

• Higher-order topological phases for time-reversal-symmetry breaking superconductivity in UTe${}_2$