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unclassified drug; uranium; uranium ditelluride; density; energy; scanning tunnelling microscopy; superconductivity; visualization; acceleration; Article; density wave; energy resource; magnetic field; mathematical model; physical parameters; scanning tunneling microscopy; superconductivity
Abstract:
Spin-triplet topological superconductors should exhibit many unprecedented electronic properties, including fractionalized electronic states relevant to quantum information processing. Although UTe2 may embody such bulk topological superconductivity 1–11, its superconductive order parameter Δ(k) remains unknown 12. Many diverse forms for Δ(k) are physically possible 12 in such heavy fermion materials 13. Moreover, intertwined 14,15 density waves of spin (SDW), charge (CDW) and pair (PDW) may interpose, with the latter exhibiting spatially modulating 14,15 superconductive order parameter Δ(r), electron-pair density 16–19 and pairing energy gap 17,20–23. Hence, the newly discovered CDW state 24 in UTe2 motivates the prospect that a PDW state may exist in this material 24,25. To search for it, we visualize the pairing energy gap with μeV-scale energy resolution using superconductive scanning tunnelling microscopy (STM) tips 26–31. We detect three PDWs, each with peak-to-peak gap modulations of around 10 μeV and at incommensurate wavevectors Pi=1,2,3 that are indistinguishable from the wavevectors Qi=1,2,3 of the prevenient 24 CDW. Concurrent visualization of the UTe2 superconductive PDWs and the non-superconductive CDWs shows that every Pi:Qi pair exhibits a relative spatial phase δϕ ≈ π. From these observations, and given UTe2 as a spin-triplet superconductor 12, this PDW state should be a spin-triplet PDW 24,25. Although such states do exist 32 in superfluid 3He, for superconductors, they are unprecedented. © 2023, The Author(s).
