近日，美国康奈尔大学Gu, Qiangqiang团队研究了UTe2超导表面态的奇宇称准粒子干涉。相关论文于2025年9月18日发表在《自然—物理学》杂志上。
虽然没有已知的材料表现出内在的拓扑超导性，其中自旋三重态电子对势具有奇宇称，但UTe2现在是主要的候选者。一般来说，超导序参量的宇称可以用波戈里乌波夫准粒子干涉成像来确定。然而，奇宇称超导体应该在最大超导能隙的能量范围内支持拓扑准粒子表面带。准粒子干涉应以准粒子表面带的电子结构为主导，只能间接地揭示体序参数的特征。
研究组证明了在UTe2的（0-11）劈裂表面，Bogoliubov准粒子带仅在超导状态下出现。然后进行高分辨率准粒子干涉测量，使他们能够探索超导表面带中的状态色散，表明它们只存在于投射到（0-11）表面的费米动量范围内。最后，研究组建立了一个理论框架来预测该表面带在（0-11）表面的准粒子干涉特征。如果块体超导序参量表现出时间反转守恒、奇宇称、a轴节点、B3u对称性，其预测结果与实验结果一致。
附：英文原文
Title: Odd-parity quasiparticle interference in the superconductive surface state of UTe2
Author: Wang, Shuqiu, Zhussupbekov, Kuanysh, Carroll, Joseph P., Hu, Bin, Liu, Xiaolong, Pangburn, Emile, Crepieux, Adeline, Pepin, Catherine, Broyles, Christopher, Ran, Sheng, Butch, Nicholas P., Saha, Shanta, Paglione, Johnpierre, Bena, Cristina, Davis, J. C. Samus, Gu, Qiangqiang
Issue&Volume: 2025-09-18
Abstract: Although no known material exhibits intrinsic topological superconductivity, where a spin-triplet electron pairing potential has odd parity, UTe2 is now the leading candidate. Generally, the parity of a superconducting order parameter can be established using Bogoliubov quasiparticle interference imaging. However, odd-parity superconductors should support a topological quasiparticle surface band at energies within the maximum superconducting energy gap. Quasiparticle interference should then be dominated by the electronic structure of the quasiparticle surface band and only reveal the characteristics of the bulk order parameter indirectly. Here we demonstrate that at the (0–11) cleave surface of UTe2, a band of Bogoliubov quasiparticles appears only in the superconducting state. Performing high-resolution quasiparticle interference measurements then allows us to explore the dispersion of states in this superconductive surface band, showing that they exist only within the range of Fermi momenta projected onto the (0–11) surface. Finally, we develop a theoretical framework to predict the quasiparticle interference signatures of this surface band at the (0–11) surface. Its predictions are consistent with the experimental results if the bulk superconducting order parameter exhibits time-reversal conserving, odd-parity, a-axis nodal, B3u symmetry.
DOI: 10.1038/s41567-025-03000-w
Source: https://www.nature.com/articles/s41567-025-03000-w