Single-Component Superconductivity in UTe${}_2$ at Ambient Pressure

Abstract

The microscopic mechanism of Cooper pairing in a superconductor leaves its fingerprint on the symmetry of the order parameter. UTe${}_2$ has been inferred to have a multi-component order parameter that entails exotic effects like time reversal symmetry breaking. However, recent experimental observations in newer-generation samples have raised questions about this interpretation, pointing to the need for a direct experimental probe of the order parameter symmetry. Here, we use pulse-echo ultrasound to measure the elastic moduli of UTe${}_2$ in samples that exhibit both one and two superconducting transitions. We demonstrate the absence of thermodynamic discontinuities in the shear elastic moduli of both single- and double-transition samples, providing direct evidence that UTe${}_2$ has a single-component superconducting order parameter. We further show that superconductivity is highly sensitive to compression strain along the $a$ and $c$ axes, but insensitive to strain along the $b$ axis. This leads us to suggest a single-component, odd-parity order parameter -- specifically the B${}_{2u}$ order parameter -- as most compatible with our data.

arXiv comment27 pages, 17 figures, 5 tables

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• Self-reconstruction of order parameter in spin-triplet superconductor UTe${}_2$
• Quasiparticle interference and spectral function of the UTe${}_2$ superconductive surface band
• Microscopic theory of pair density waves in spin-orbit coupled Kondo lattice
• Magnetic signatures of pressure-induced multicomponent superconductivity in UTe${}_2$
• Thermal conductivity of nonunitary triplet superconductors: application to UTe${}_2$
• Dramatic elastic response at the critical end point in UTe${}_2$
• Two-dimensional flat band on the (011) surface of UTe${}_2$: Implication for STM measurements with a superconducting tip
• Higher-order topological phases for time-reversal-symmetry breaking superconductivity in UTe${}_2$
• Magnetic edge fields in UTe${}_2$ near zero background fields
• Nodal Superconductivity of UTe${}_2$ Probed by Field-Angle-Resolved Specific Heat on a Crystal with $T_{\mathrm{c}}=2.1$ K
• A unified theoretical framework for Kondo superconductors: Periodic Anderson impurities with attractive pairing and Rashba spin-orbit coupling
• Revealing isotropic abundant low-energy excitations in UTe${}_2$ through complex microwave surface impedance
• Quasiparticle Interference of Spin-Triplet Superconductors: Application to UTe${}_2$
• Pressure-enhanced $f$-electron orbital weighting in UTe2 mapped by quantum interferometry
• Electronic structure of UTe${}_2$ under pressure
• Theoretical Study of Impurity Effects on Superconductivity in UTe2
• Chiral topological superconductivity in twisted bilayer and double bilayer graphene
• Raman response of collective modes in multicomponent superconductors
• Evidence of intertwined pair density and charge density wave orders in UTe2