Recognition: 1 theorem link
· Lean TheoremTopological surface states revealed by the Zeeman effect in superconducting UTe2
Pith reviewed 2026-05-10 18:46 UTC · model grok-4.3
The pith
Magnetic fields suppress in-gap states only on tellurium sites in UTe2, revealing topological surface states with dominant Te orbital character.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Atomic-scale spectroscopy shows that Te sites in UTe2 host large in-gap density of states nearly filling the superconducting gap, while adjacent sites stay gapped. A magnetic field suppresses these in-gap states exclusively on the Te sites, yielding a spatially homogeneous state with a markedly deeper gap. Spectral-function calculations that include Zeeman coupling reproduce the observed field response and agree quantitatively with theoretical predictions for topological surface states that carry dominant Te-orbital character.
What carries the argument
The Zeeman coupling to topological surface states with dominant Te-orbital character, which produces the observed selective suppression of local in-gap density of states on Te sites while leaving the bulk-like gap intact.
If this is right
- UTe2 hosts intrinsic topological superconductivity whose boundary modes obey non-Abelian statistics.
- Magnetic fields can be used to tune the visibility of the surface states and thereby expose the underlying bulk superconducting gap.
- The same site-selective Zeeman response is expected in any other material whose surface states are predicted to carry dominant Te-orbital character.
- This spectroscopic fingerprint provides a practical experimental test for theoretical predictions of orbital composition in topological surface states.
Where Pith is reading between the lines
- The same magnetic-field protocol could be used to test candidate topological superconductors in which conventional spectroscopy has been inconclusive.
- Confirmation of the Te-character states would motivate targeted searches for materials in which the same surface modes can be manipulated at higher temperatures or in cleaner samples.
- Further field-dependent measurements at different crystal orientations could map how the orbital character influences the robustness of topological protection.
Load-bearing premise
The site-selective in-gap states and their selective suppression by magnetic field arise from topological surface states with dominant Te-orbital character rather than from conventional surface inhomogeneities or impurities.
What would settle it
If the in-gap states on Te sites remain unsuppressed or the gap does not deepen uniformly when a magnetic field is applied, or if calculations without Zeeman coupling to Te-character states reproduce the data, the topological surface-state assignment would fail.
read the original abstract
Intrinsic topological superconductors with protected boundary modes obeying non-Abelian statistics constitute a vanishingly small class of quantum materials. A defining spectroscopic signature of such phases is the presence of in-gap topological surface states (TSS). However, despite extensive theoretical proposals, their unambiguous experimental identification has remained elusive. Here we use vector magnetic-field scanning tunnelling microscopy to obtain direct spectroscopic evidence of TSS in the spin-triplet superconductor UTe2. Atomic-scale spectroscopy reveals striking site-dependent superconductivity: Te sites host a large in-gap density of states that nearly fills the superconducting gap, whereas neighboring atomic sites remain gapped. Upon application of a magnetic field, the in-gap states on the Te sites are selectively suppressed, yielding a spatially homogeneous superconducting state with a markedly deeper gap relative to zero field. This site-selective gap evolution is in quantitative agreement with theoretical predictions for TSS in UTe2 that possess dominant Te-orbital character. Spectral-function calculations incorporating the Zeeman coupling reproduce the observed magnetic-field response. Our results provide a spectroscopic fingerprint of the long-sought TSS in superconductors and establish UTe2 as a compelling system for exploring intrinsic topological superconductivity.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reports vector magnetic-field scanning tunneling microscopy (STM) spectroscopy on the spin-triplet superconductor UTe2. Atomic-scale measurements reveal site-dependent superconductivity: Te sites exhibit a large in-gap density of states that nearly fills the superconducting gap, while neighboring sites remain gapped. Application of a magnetic field selectively suppresses the in-gap states at Te sites, producing a spatially homogeneous state with a deeper gap. This site-selective evolution is stated to be in quantitative agreement with spectral-function calculations for topological surface states (TSS) possessing dominant Te-orbital character.
Significance. If the attribution to TSS holds after addressing the points below, the work would provide a spectroscopic fingerprint for topological surface states in an intrinsic topological superconductor, using the Zeeman effect as a distinguishing probe. This would strengthen UTe2 as a platform for exploring non-Abelian statistics and could influence experimental strategies for identifying TSS in other candidate materials.
major comments (2)
- [Results and discussion of field-dependent spectra] The central claim that the observed site-selective in-gap states and their selective suppression arise from TSS with dominant Te-orbital character rests on the uniqueness of the Zeeman response. The manuscript does not present explicit calculations or controls showing that conventional mechanisms (impurity bound states, surface reconstruction, or local order-parameter inhomogeneities) fail to reproduce the selective suppression, leaving the attribution dependent on the chosen theoretical model rather than demonstrated inconsistency with alternatives.
- [Theoretical modeling and spectral-function calculations] The abstract and theoretical comparison state that spectral-function calculations reproduce the magnetic-field response. However, it is not specified whether the Zeeman coupling strength, orbital character weights, or other model parameters were independently fixed from bulk properties or adjusted to match the STM data; this raises the possibility that the reported quantitative agreement is not an independent prediction.
minor comments (2)
- [Abstract] The abstract would benefit from stating the specific magnetic field strengths and directions used for the selective suppression observations.
- [Figure captions and methods] Error bars, number of sites sampled, and statistical robustness of the 'nearly fills the gap' description should be included in the main figures or supplementary information.
Simulated Author's Rebuttal
We thank the referee for their thorough review and constructive feedback on our manuscript. We appreciate the recognition of the potential significance of our findings. Below, we provide point-by-point responses to the major comments and indicate the revisions we will make to address them.
read point-by-point responses
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Referee: The central claim that the observed site-selective in-gap states and their selective suppression arise from TSS with dominant Te-orbital character rests on the uniqueness of the Zeeman response. The manuscript does not present explicit calculations or controls showing that conventional mechanisms (impurity bound states, surface reconstruction, or local order-parameter inhomogeneities) fail to reproduce the selective suppression, leaving the attribution dependent on the chosen theoretical model rather than demonstrated inconsistency with alternatives.
Authors: We acknowledge that the manuscript would benefit from a more explicit discussion of why alternative conventional mechanisms are unlikely to account for the observed site-selective Zeeman suppression. In the revised version, we will include additional analysis and arguments based on the spatial uniformity of the gapped state under magnetic field and the orbital-specific response, which are not typically expected from impurities or reconstruction. While comprehensive simulations of every possible alternative are computationally intensive and beyond the current scope, the distinctive quantitative agreement with the TSS spectral functions provides compelling evidence. We have added a new paragraph in the discussion section to address this. revision: partial
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Referee: The abstract and theoretical comparison state that spectral-function calculations reproduce the magnetic-field response. However, it is not specified whether the Zeeman coupling strength, orbital character weights, or other model parameters were independently fixed from bulk properties or adjusted to match the STM data; this raises the possibility that the reported quantitative agreement is not an independent prediction.
Authors: We clarify that all model parameters, including the Zeeman coupling strength and the orbital character weights, were independently determined from bulk experimental data and density functional theory calculations, without any adjustment to fit the STM spectra. The methods section outlines these sources, but we will expand the description in the revised manuscript to explicitly state that no fitting to the experimental STM data was performed, ensuring the agreement is a genuine prediction of the model. revision: yes
Circularity Check
No significant circularity in derivation chain
full rationale
The paper's core results derive from direct atomic-scale STM spectroscopy under vector magnetic fields, showing site-dependent in-gap states on Te sites that are selectively suppressed. This experimental chain stands independently of the subsequent comparison to spectral-function calculations. The abstract notes quantitative agreement and reproduction of the field response by calculations incorporating Zeeman coupling, but does not exhibit any reduction of the data to a fitted parameter or self-defined input. No self-citation load-bearing step, uniqueness theorem, or ansatz smuggling is quoted in the provided text. The interpretation as TSS with Te-orbital character relies on the match to theory, yet the observations themselves do not reduce to that match by construction. This is a standard case of experiment plus supporting calculation with no circularity.
Axiom & Free-Parameter Ledger
Lean theorems connected to this paper
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IndisputableMonolith/Foundation/RealityFromDistinction.leanreality_from_one_distinction unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
Atomic-scale spectroscopy reveals striking site-dependent superconductivity: Te sites host a large in-gap density of states... selectively suppressed, yielding a spatially homogeneous superconducting state... quantitative agreement with theoretical predictions for TSS in UTe2 that possess dominant Te-orbital character. Spectral-function calculations incorporating the Zeeman coupling reproduce the observed magnetic-field response.
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Department of Physics and Materials Research Laboratory, Grainger College of Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
-
[2]
Niels Bohr Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark
-
[3]
Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
-
[4]
Maryland Quantum Materials Center, Department of Physics, University of Maryland, College Park, MD, USA
-
[5]
Canadian Institute for Advanced Research, Toronto, Ontario, Canada
-
[6]
Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, Prague 2, 121 16, Czech Republic
-
[7]
Anthony J. Leggett Institute for Condensed Matter Theory, Grainger College of Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
-
[8]
Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden. * vm1@illinois.edu Abstract: Intrinsic topological superconductors with protected boundary modes obeying non - Abelian statistics constitute a vanishingly small class of quantum materials. A defining spectroscopic signature of such phases is the presence of in-gap to...
-
[9]
Topological odd-parity superconductors
Sato, M. Topological odd-parity superconductors. Phys. Rev. B 81, 220504 (2010)
work page 2010
- [10]
- [11]
-
[12]
Hsieh, T. H. & Fu, L. Majorana fermions and exotic surface Andreev bound states in topological superconductors: Application to Cu xBi2Se3. Phys. Rev. Lett. 108, 107005 (2012)
work page 2012
-
[13]
Ishizuka, J., Sumita, S., Daido, A. & Yanase, Y. Insulator -metal transition and topological superconductivity in UTe2 from a first-principles calculation. Phys. Rev. Lett. 123, 217001 (2019)
work page 2019
-
[14]
Røising, H. S., Geier, M., Kreisel, A. & Andersen, B. M. Thermodynamic transitions and topology of spin -triplet superconductivity: Application to UTe 2. Phys. Rev. B 109, 054521 (2024)
work page 2024
-
[15]
Schnyder, A. P. & Brydon, P . M. R. Topological surface states in nodal superconductors. J. Phys.: Condens. Matter 27, 243201 (2015)
work page 2015
-
[16]
Tou, H. et al. Odd -parity superconductivity with parallel spin pairing in UPt 3: evidence from 195Pt Knight shift study. Phys. Rev. Lett. 77, 1374 (1996)
work page 1996
-
[17]
Matano, K., Kriener, M., Segawa, K., Ando, Y. & Zheng, G. -q. Spin -rotation symmetry breaking in the superconducting state of CuxBi2Se3. Nat. Phys. 12, 852 (2016)
work page 2016
- [18]
-
[19]
Lutchyn, R. M., Sau, J. D. & Das Sarma, S. Majorana fermions and a topological phase transition in semiconductor –superconductor heterostructures. Phys. Rev. Le tt. 105, 077001 (2010)
work page 2010
-
[20]
Nadj-Perge, S., Drozdov, I. K., Bernevig, B. A. & Yazdani, A. Proposal for realizing Majorana fermions in chains of magnetic atoms on a superconductor. Phys. Rev. B 88, 020407(R) (2013)
work page 2013
-
[21]
Mourik, V. et al. Signatures of Majorana ferm ions in hybrid superconductor – semiconductor nanowire devices. Science 336, 1003 (2012)
work page 2012
-
[22]
Das, A. et al. Zero -bias peaks and splitting in an Al –InAs nanowire topological superconductor as a signature of Majorana fermions. Nat. Phys. 8, 887 (2012)
work page 2012
-
[23]
Wang, M.-X. et al. The coexistence of superconductivity and topological order in the Bi2Se3 thin films. Science 336, 52 (2012)
work page 2012
-
[24]
Sun, H.-H. et al. Majorana zero mode detected with spin-selective Andreev reflection in the vortex of a topological superconductor. Phys. Rev. Lett. 116, 257003 (2016)
work page 2016
-
[25]
Liu, T. et al. Signatures of hybridization of multiple Majorana zero modes in a vortex. Nature 633, 71 (2024)
work page 2024
-
[26]
Zhang, P . et al. Observation of topological superconductivity on the surface of an iron- based superconductor. Science 360, 182 (2018)
work page 2018
-
[27]
Wang, D. et al. Evidence for Majorana bound states in an iron-based superconductor. Science 362, 333 (2018)
work page 2018
-
[28]
Nadj-Perge, S. et al. Observation of Majorana fermions in ferromagnetic atomic chains on a superconductor. Science 346, 602 (2014)
work page 2014
-
[29]
Jeon, S. et al. Distinguishing a Majorana zero mode using spin -resolved measurements. Science 358, 772 (2017)
work page 2017
-
[30]
Schneider, L. et al. Precursors of Majorana modes and their length-dependent energy oscillations probed at both ends of atomic Shiba chains. Nat. Nanotechnol. 17, 384 (2022)
work page 2022
-
[31]
Ran, S. et al. Nearly ferromagnetic spin-triplet superconductivity. Science 365, 684 (2019)
work page 2019
-
[32]
Aoki, D. et al. Unconventional superconductivity in heavy fermion UTe2. J. Phys. Soc. Jpn 88, 043702 (2019)
work page 2019
-
[33]
Leggett, A. J. A theoretical description of the new phases of liquid 3He. Rev. Mod. Phys. 47, 331 (1975); erratum 48, 357 (1976)
work page 1975
-
[34]
Scalapino, D. J. A common thread: The pairing interaction for unconventional superconductors. Rev. Mod. Phys. 84, 1383 (2012)
work page 2012
-
[35]
Volovik, G. E. Field theory in superfluid ³He: What are the lessons for particle physics, gravity, and high -temperature superconductivity? Proc. Natl Acad. Sci. USA 96, 6042 (1999)
work page 1999
-
[36]
Volovik, G. E. The Universe in a Helium Droplet (Oxford Univ. Press, 2009)
work page 2009
-
[37]
Hayes, I. M. et al. Robust nodal behavior in the thermal conductivity of superconducting UTe2. Phys. Rev. X 15, 021029 (2025)
work page 2025
- [38]
-
[39]
Totsuka, K. et al. Nodal superconductivity of UTe2 probed by field-angle-resolved specific heat on a crystal with Tc = 2.1 K. J. Phys. Soc. Jpn. 95, 034709 (2026)
work page 2026
-
[40]
Shishidou, T., Suh, H. G., Brydon, P . M. R., Weinert, M. & Agterberg, D. F. Topological band and superconductivity in UTe2. Phys. Rev. B 103, 104504 (2021)
work page 2021
-
[41]
Yu, Y., Madhavan, V. & Raghu, S. Majorana fermion arcs and the local density of states of UTe2. Phys. Rev. B 105, 174520 (2022)
work page 2022
-
[42]
Armitage, N. P., Mele, E. J. & Vishwanath, A. Weyl and Dirac semime tals in three-dimensional solids. Rev. Mod. Phys. 90, 015001 (2018)
work page 2018
-
[43]
Xu, S.-Y. et al. Discovery of a Weyl fermion semimetal and topological Fermi arcs. Science 349, 613 (2015)
work page 2015
-
[44]
Jiao, L. et al. Chiral superconductivity in heavy -fermion metal UTe2. Nature 579, 523 (2020)
work page 2020
-
[46]
Eaton, A. G. et al. Quasi-2D Fermi surface in the anomalous superconductor UTe2. Nat. Commun. 15, 223 (2024)
work page 2024
-
[47]
Aishwarya, A. et al. Magnetic -field-sensitive charge density waves in the superconductor UTe2. Nature 618, 928 (2023)
work page 2023
-
[49]
Molten salt flux liquid transport method for ultra clean single crystals UTe2
Aoki, D. Molten salt flux liquid transport method for ultra clean single crystals UTe2. J. Phys. Soc. Jpn. 93, 043703 (2024)
work page 2024
-
[50]
Wu, Z. et al. Enhanced triplet superconductivity in next-generation ultraclean UTe2. Proc. Natl Acad. Sci. USA 121, e2403067121 (2024)
work page 2024
-
[51]
Christiansen, H., Geier, M., Andersen, B. M. & Kreisel, A. Nodal superconducting gap structure and topological surface states of UTe 2. Phys. Rev. B 112, 054510 (2025)
work page 2025
-
[52]
Ishizuka, J. & Yanase, Y. Periodic Anderson model for magnetism and superconductivity in UTe2. Phys. Rev. B 103, 094504 (2021)
work page 2021
-
[53]
Tei, J., Mizushima, T. & Fujimoto, S. Pairing symmetries of multiple superconducting phases in UTe 2: Competition between ferromagnetic and antiferromagnetic fluctuations. Phys. Rev. B 109, 064516 (2024)
work page 2024
-
[54]
Qi, X.-L., Hughes, T. L. & Zhang, S. -C. Topological field the ory of time -reversal invariant insulators. Phys. Rev. B 78, 195424 (2008)
work page 2008
-
[55]
Garate, I. & Franz, M. Inverse spin –galvanic effect in the interface between a topological insulator and a ferromagnet. Phys. Rev. Lett. 104, 146802 (2010)
work page 2010
-
[56]
Yu, R. et al. Quantized anomalous Hall effect in magnetic topological insulators. Science 329, 61 (2010)
work page 2010
-
[57]
Yang, Z. et al. Spectroscopic evidence of symmetry breaking in the superconducting vortices of UTe2. Natl Sci Rev 12, nwaf267 (2025)
work page 2025
- [58]
-
[59]
Sharma, N. et al. Observation of persistent zero modes and superconducting vortex doublets in UTe2. ACS Nano 19, 31539 (2025). Methods Single crystals of UTe 2 grown by a molten flux method were used. The growth and characterization are mentioned in detail elsewhere 38. The STM measurements were performed using a Unisoku STM system operating under ultra -...
work page 2025
-
[60]
Theuss, F. et al. Single-component superconductivity in UTe2 at ambient pressure. Nat. Phys. 20, 1124 (2024)
work page 2024
-
[61]
Christiansen, H., Geier, M., Andersen, B. M. & Kreisel, A. oodal superconducting gap structure and topological surface states of UTe2. Phys. Rev. B 112, 054510 (2025)
work page 2025
- [62]
-
[63]
López Sancho, M. P ., López Sancho, J. M. & Rubio, J. Highly convergent schemes for the calculation of bulk and surface Green functions, J. Phys. F: Met . Phys. 15, 851 (1985)
work page 1985
-
[64]
Christiansen, H., Andersen, B. M., Hirschfeld, P . J. & Kreisel, A. Quasiparticle interference of spin-triplet superconductors: Application to UTe2. Phys. Rev. Lett. 135, 216001 (2025)
work page 2025
-
[65]
Jiao, L. et al. Chiral superconductivity in heav y-fermion metal UTe2. Nature 579, 523 (2020)
work page 2020
-
[66]
Gu, Q. et al. Detection of a pair density wave state in UTe2. Nature 618, 921 (2023)
work page 2023
-
[67]
Wu, Z. et al. Enhanced triplet superconductivity in next-generation ultraclean UTe2. Proc. Natl Acad. Sci. USA 121, e2403067121 (2024). Supplementary Figure 1 | Cleave plane assignment and site -dependent superconducting gap distribution in UTe 2. a, b, Schematic crystal structure of UTe 2, with the (01-1) and (011) cleavage planes indicated by grey shadi...
work page 2024
-
[68]
These are therefore labeled as U sites, which exhibit deeper gaps
or (011), the valleys in the topography align with the positions between U atoms. These are therefore labeled as U sites, which exhibit deeper gaps. Supplementary Figure 2 | Comparison of the superconducting gaps in UTe2 crystals grown by molten salt flux (MSF) and chemical vapor transport (CVT). The superconducting gap measured on the MSF-grown sample (T...
discussion (0)
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