SKM 2021 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 29: Topological Superconductors

TT 29.2: Talk

Friday, October 1, 2021, 13:45–14:00, H7

Accidental Two-Component Order Parameter in UTe₂ — •Florian Theuss¹, Gael Grissonnanche¹, Nicholas Butch^2,3, Johnpierre Paglione³, Sheng Ran⁴, Kelly Nygren⁵, Peter Ko⁵, and Brad Ramshaw¹ — ¹Cornell University, Ithaca, NY, USA — ²NIST, College Park, MD, USA — ³University of Maryland, College Park, MD, USA — ⁴Washington University, St. Louis, MO, USA — ⁵CHESS, Ithaca, NY, USA

The recently discovered unconventional superconductor UTe₂ is a promising candidate to host time-reversal symmetry breaking (TRSB) in the ordered state, below about 1.6 K. TRSB, indicated by a field trainable Kerr effect, would require a two-component order parameter. Due to the orthorhombic crystal symmetry of UTe₂, a two-component order parameter is expected to be accidental, resulting in two successive superconducting phase transitions. We address this question with Resonant Ultrasound Spectroscopy, where we measure mechanical resonance frequencies of the sample and can resolve two jumps in their temperature dependence with close to part per million resolution. This gives us information about the possibility of a two-component order parameter and constrains its symmetry. Additionally, we perform near-field/far-field high-energy X-ray diffraction experiments to investigate sample homogeneity.

This work is supported by the Office of Basic Energy Sciences of the United States Department of Energy under award no. DE-SC0020143 and partially based upon research conducted at the Materials Solutions Network at CHESS (MSN-C) which is supported by the Air Force Research Laboratory under award FA8650-19-2-5220.