Although nodal spin-triplet topological superconductivity appears probable in UTe2, its superconductive order-parameter Δk 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 Δk 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 Δk 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.
@article{arxiv.2501.16636,
title = {Pair Wavefunction Symmetry in UTe2 from Zero-Energy Surface State Visualization},
author = {Qiangqiang Gu and Shuqiu Wang and Joseph P. Carroll and Kuanysh Zhussupbekov and Christopher Broyles and Sheng Ran and Nicholas P. Butch and Shanta Saha and Johnpierre Paglione and Xiaolong Liu and J. C. Séamus Davis and Dung-Hai Lee},
journal= {arXiv preprint arXiv:2501.16636},
year = {2025}
}