Single-Component Superconductivity in UTe2 at Ambient Pressure

Published

July 1, 2024

Author(s)

Florian Theuss, Avi Shragai, Gael Grissonnanche, Ian Hayes, Shanta Saha, Yun Eo, Alonso Suarez, Tatsuya Shishidou, Nicholas Butch, Johnpierre Paglione, B. Ramshaw

Abstract

The microscopic mechanism of Cooper pairing in a superconductor leaves its fingerprint on the symmetry of the order parameter. UTe2 has previously been inferred to have a multi-component order parameter, in part due to the apparent presence of a two-step superconducting transition in some samples. However, recent experimental observations in newer-generation samples have raised questions about this interpretation, pointing to the need for a direct probe of the order parameter symmetry. Here we use pulse-echo ultrasound to measure the elastic moduli of UTe2 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 UTe2 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 B2u order parameter—as most compatible with our data.

Citation

Nature Physics

Volume

20

Pub Type

Journals

Download Paper

https://doi.org/10.1038/s41567-024-02493-1

Local Download

Keywords

spin-triplet superconductivity, ultrasound, elastic constants

Citation

Theuss, F. , Shragai, A. , Grissonnanche, G. , Hayes, I. , Saha, S. , Eo, Y. , Suarez, A. , Shishidou, T. , Butch, N. , Paglione, J. and Ramshaw, B. (2024), Single-Component Superconductivity in UTe2 at Ambient Pressure, Nature Physics, [online], https://doi.org/10.1038/s41567-024-02493-1, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957690 (Accessed October 13, 2025)