A distinctive identifier of nodal intrinsic topological superconductivity (ITS) would the appearance of an Andreev bound state on crystal surfaces parallel to the nodal axis, in the form of a topological quasiparticle surface band (QSB) appearing only for T<TC. Moreover, theory shows that specific QSB characteristics observable in tunneling to an s-wave superconductor can distinguish between chiral and non-chiral ITS order parameter Δk. To search for such phenomena in UTe2, s-wave superconductive scan-tip scanning tunneling microscopy (STM) imaging was employed. It reveals an intense zero-energy Andreev conductance maximum at the UTe2 (0-11) crystal termination. Development of the zero-energy Andreev conductance peak into two finite-energy particle-hole symmetric conductance maxima as the tunnel barrier is reduced, then signifies that UTe2 superconductivity is non-chiral. Quasiparticle interference imaging (QPI) for an ITS material should be dominated by the QSB for energies within the superconductive energy gap ∣E∣≤Δ, so that bulk Δ(k) characteristics of the ITS can only be detected excursively. Again using a superconducting scan-tip, the in-gap quasiparticle interference patterns of the QSB of UTe2 were visualized. Specifically, a band of Bogoliubov quasiparticles appears as a characteristic sextet qi :i=1−6 of interference wavevectors showing that QSB dispersions k(E) occur only for energies ∣E∣≤Δmax and only within the range of Fermi momenta projected onto the (0-11) crystal surface. In combination, these phenomena are consistent with a bulk Δ(k) exhibiting spin triplet, time-reversal conserving, odd-parity, a-axis nodal, B3u symmetry in UTe2.
@article{arxiv.2602.02490,
title = {Visualizing the Odd-parity Superconducting Order Parameter and its Quasiparticle Surface Band in UTe2},
author = {Shuqiu Wang and J. C. Séamus Davis},
journal= {arXiv preprint arXiv:2602.02490},
year = {2026}
}