Pair Wavefunction Symmetry in UTe2 from Zero-Energy Surface State Visualization

Qiangqiang Gu; Shuqiu Wang; Joseph P. Carroll; Kuanysh Zhussupbekov; Christopher Broyles; Sheng Ran; Nicholas P. Butch; Shanta Saha; Johnpierre Paglione; Xiaolong Liu; J. C. Séamus Davis; Dung-Hai Lee

doi:10.1126/science.adk7219

arXiv · 2501.16636

Pair Wavefunction Symmetry in UTe2 from Zero-Energy Surface State Visualization

Qiangqiang Gu·Shuqiu Wang·Joseph P. Carroll·Kuanysh Zhussupbekov·Christopher Broyles·Sheng Ran·Nicholas P. Butch·Shanta Saha·Johnpierre Paglione·Xiaolong Liu·J. C. Séamus Davis·Dung-Hai Lee

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Abstract

Although nodal spin-triplet topological superconductivity appears probable in UTe2, its superconductive order-parameter $\Delta_k$ remains unestablished. In theory, a distinctive identifier would be the existence of a superconductive topological surface band (TSB), which could facilitate zero-energy Andreev tunneling to an s-wave superconductor, and also distinguish a chiral from non-chiral $\Delta_k$ via enhanced s-wave proximity. Here we employ s-wave superconductive scan-tips and detect intense zero-energy Andreev conductance at the UTe2 (0-11) termination surface. Imaging reveals sub-gap quasiparticle scattering interference signatures with a-axis orientation. The observed zero-energy Andreev peak splitting with enhanced s-wave proximity, signifies that $\Delta_k$ of UTe2 is a non-chiral state: B1u, B2u or B3u. However, if the quasiparticle scattering along the a-axis is internodal, then a non-chiral B3u state is the most consistent for UTe2.

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Qiangqiang Gu, Shuqiu Wang, Joseph P. Carroll, Kuanysh Zhussupbekov, Christopher Broyles, Sheng Ran, Nicholas P. Butch, Shanta Saha, Johnpierre Paglione, Xiaolong Liu, J. C. Séamus Davis, Dung-Hai Lee. 2025-01-28. Pair Wavefunction Symmetry in UTe2 from Zero-Energy Surface State Visualization. https://doi.org/10.1126/science.adk7219

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