Absence of Spontaneous Magnetic Fields due to Time-Reversal Symmetry Breaking in Bulk Superconducting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>UTe</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>
N. Azari, M. Yakovlev, N. Rye, S. R. Dunsiger, Shyam Sundar, Mitchell M. Bordelon, S. M. Thomas, J. D. Thompson, P. F. S. Rosa, J. E. Sonier
Abstract
We have investigated the low-temperature local magnetic properties in the bulk of molten salt-flux (MSF)-grown single crystals of the candidate odd-parity superconductor UTe2 by zero-field muon spin relaxation (μSR). In contrast to previous μSR studies of UTe2 single crystals grown by a chemical vapor transport method, we find no evidence of magnetic clusters or electronic moments fluctuating slow enough to cause a discernible relaxation of the zero-field μSR asymmetry spectrum. Consequently, our measurements on MSF-grown single crystals rule out the generation of spontaneous magnetic fields in the bulk that would occur near impurities or lattice defects if the superconducting state of UTe2 breaks time-reversal symmetry. This result suggests that UTe2 is characterized by a single-component superconducting order parameter.Received 18 August 2023Accepted 18 October 2023DOI:https://doi.org/10.1103/PhysRevLett.131.226504© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasSuperconducting order parameterPhysical SystemsSuperconductivityTechniquesMuon spin relaxation & rotationCondensed Matter, Materials & Applied Physics