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Electronic properties of the bulk and surface states of Fe1+yTe1−xSex

Nature Materials volume 20, pages 1221–1227 (2021)Cite this article

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Abstract

The idea of employing non-Abelian statistics for error-free quantum computing ignited interest in reports of topological surface superconductivity and Majorana zero modes (MZMs) in FeTe0.55Se0.45. However, the topological features and superconducting properties are not observed uniformly across the sample surface. The understanding and practical control of these electronic inhomogeneities present a prominent challenge for potential applications. Here, we combine neutron scattering, scanning angle-resolved photoemission spectroscopy, and microprobe composition and resistivity measurements to characterize the electronic state of Fe1+yTe1−xSex. We establish a phase diagram in which the superconductivity is observed only at sufficiently low Fe concentration, in association with distinct antiferromagnetic correlations, whereas the coexisting topological surface state occurs only at sufficiently high Te concentration. We find that FeTe0.55Se0.45 is located very close to both phase boundaries, which explains the inhomogeneity of superconducting and topological states. Our results demonstrate the compositional control required for use of topological MZMs in practical applications.

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Fig. 1: Magnetic and superconducting phases in Fe1+yTe1−xSex.
Fig. 2: Local electrical, chemical and photoemission properties of Fe1+yTe1−xSex.
Fig. 3: Typical distribution of local chemical composition and electronic properties in the sample.
Fig. 4: Phase diagram of competing bulk and surface quantum states in Fe1+yTe1−xSex.
Fig. 5: Statistics of local phases and chemical composition in Fe1+yTe1−xSex samples.

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All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Information. Additional data are available from the corresponding author upon reasonable request.

References

  1. Castelvecchi, D. Quantum computers ready to leap out of the lab in 2017. Nature 541, 9–10 (2017).

    Article  CAS  Google Scholar 

  2. Wendin, G. Quantum information processing with superconducting circuits: a review. Rep. Prog. Phys. 80, 106001 (2017).

    Article  CAS  Google Scholar 

  3. Arute, F. et al. Quantum supremacy using a programmable superconducting processor. Nature 574, 505–510 (2019).

    Article  CAS  Google Scholar 

  4. Nayak, C., Simon, S. H., Stern, A., Freedman, M. & Sarma, S. D. Non-Abelian anyons and topological quantum computation. Rev. Mod. Phys. 80, 1083–1159 (2008).

    Article  CAS  Google Scholar 

  5. Sarma, S. D., Freedman, M. & Nayak, C. Majorana zero modes and topological quantum computation. npj Quantum Inf. 1, 15001 (2015).

    Article  Google Scholar 

  6. Zhang, P. et al. Observation of topological superconductivity on the surface of an iron-based superconductor. Science 360, 182–186 (2018).

    Article  CAS  Google Scholar 

  7. Rameau, J. D., Zaki, N., Gu, G. D., Johnson, P. D. & Weinert, M. Interplay of paramagnetism and topology in the Fe-chalcogenide high-Tc superconductors. Phys. Rev. B 99, 205117 (2019).

    Article  CAS  Google Scholar 

  8. Zaki, N., Gu, G., Tsvelik, A., Wu, C. & Johnson, P. D. Time-reversal symmetry breaking in the Fe-chalcogenide superconductors. Proc. Natl Acad. Sci. USA 118, e2007241118 (2021).

    Article  CAS  Google Scholar 

  9. Wang, D. et al. Evidence for Majorana bound states in an iron-based superconductor. Science 362, 333–335 (2018).

    Article  CAS  Google Scholar 

  10. Zhu, S. et al. Nearly quantized conductance plateau of vortex zero mode in an iron-based superconductor. Science 367, 189–192 (2020).

    Article  CAS  Google Scholar 

  11. Kong, L. et al. Half-integer level shift of vortex bound states in an iron-based superconductor. Nat. Phys. 15, 1181–1187 (2019).

    Article  CAS  Google Scholar 

  12. Machida, T. et al. Zero-energy vortex bound state in the superconducting topological surface state of Fe(Se,Te). Nat. Mater. 18, 811–815 (2019).

    Article  CAS  Google Scholar 

  13. Wang, Z. et al. Evidence for dispersing 1D Majorana channels in an iron-based superconductor. Science 367, 104–108 (2020).

    Article  CAS  Google Scholar 

  14. Chen, M. et al. Discrete energy levels of Caroli-de Gennes-Matricon states in quantum limit in FeTe0.55Se0.45. Nat. Commun. 9, 970 (2018).

    Article  CAS  Google Scholar 

  15. Cho, D., Bastiaans, K. M., Chatzopoulos, D., Gu, G. D. & Allan, M. P. A strongly inhomogeneous superfluid in an iron-based superconductor. Nature 571, 541–545 (2019).

    Article  CAS  Google Scholar 

  16. Johnson, P. D. et al. Spin-orbit interactions and the nematicity observed in the Fe-based superconductors. Phys. Rev. Lett. 114, 167001 (2015).

    Article  CAS  Google Scholar 

  17. Wang, Z. et al. Topological nature of the FeSe0.5Te0.5 superconductor. Phys. Rev. B 92, 115119 (2015).

    Article  CAS  Google Scholar 

  18. Xu, G., Lian, B., Tang, P., Qi, X.-L. & Zhang, S.-C. Topological superconductivity on the surface of Fe-based superconductors. Phys. Rev. Lett. 117, 047001 (2016).

    Article  CAS  Google Scholar 

  19. Wu, X., Qin, S., Liang, Y., Fan, H. & Hu, J. Topological characters in FeTe1−xSex thin films. Phys. Rev. B 93, 115129 (2016).

    Article  CAS  Google Scholar 

  20. Zhang, P. et al. Multiple topological states in iron-based superconductors. Nat. Phys. 15, 41–47 (2019).

    Article  CAS  Google Scholar 

  21. Peng, X.-L. et al. Observation of topological transition in high-Tc superconducting monolayer FeTe1−xSex films on SrTiO3(001). Phys. Rev. B 100, 155134 (2019).

    Article  CAS  Google Scholar 

  22. Yin, Z. P., Haule, K. & Kotliar, G. Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides. Nat. Mater. 10, 932–935 (2011).

    Article  CAS  Google Scholar 

  23. Zaliznyak, I. A. et al. Unconventional temperature enhanced magnetism in Fe1.1Te. Phys. Rev. Lett. 107, 216403 (2011).

    Article  CAS  Google Scholar 

  24. Ieki, E. et al. Evolution from incoherent to coherent electronic states and its implications for superconductivity in FeTe1−xSex. Phys. Rev. B 89, 140506 (2014).

    Article  CAS  Google Scholar 

  25. Liu, Z. K. et al. Experimental observation of incoherent-coherent crossover and orbital-dependent band renormalization in iron chalcogenide superconductors. Phys. Rev. B 92, 235138 (2015).

    Article  CAS  Google Scholar 

  26. Yi, M. et al. Observation of universal strong orbital-dependent correlation effects in iron chalcogenides. Nat. Commun. 6, 7777 (2015).

    Article  CAS  Google Scholar 

  27. Yi, M., Zhang, Y., Shen, Z.-X. & Lu, D. Role of the orbital degree of freedom in iron-based superconductors. npj Quantum Mater. 2, 57 (2017).

    Article  CAS  Google Scholar 

  28. Zaliznyak, I. et al. Spin-liquid polymorphism in a correlated electron system on the threshold of superconductivity. Proc. Natl Acad. Sci. USA 112, 10316–10320 (2015).

    Article  CAS  Google Scholar 

  29. Xu, Z. et al. Thermal evolution of antiferromagnetic correlations and tetrahedral bond angles in superconducting FeTe1−xSex. Phys. Rev. B 93, 104517 (2016).

    Article  CAS  Google Scholar 

  30. Zaliznyak, I. A. et al. Continuous magnetic and structural phase transitions in Fe1+yTe. Phys. Rev. B 85, 085105 (2012).

    Article  CAS  Google Scholar 

  31. Fobes, D. et al. Ferro-orbital ordering transition in iron telluride Fe1+yTe. Phys. Rev. Lett. 112, 187202 (2014).

    Article  CAS  Google Scholar 

  32. McQueen, T. M. et al. Extreme sensitivity of superconductivity to stoichiometry in Fe1+δSe. Phys. Rev. B 79, 014522 (2009).

    Article  CAS  Google Scholar 

  33. Liu, T. J. et al. Charge-carrier localization induced by excess Fe in the superconductor Fe1+yTe1−xSex. Phys. Rev. B 80, 174509 (2009).

    Article  CAS  Google Scholar 

  34. Wen, J. et al. Short-range incommensurate magnetic order near the superconducting phase boundary in Fe1+δTe1−xSex. Phys. Rev. B 80, 104506 (2009).

    Article  CAS  Google Scholar 

  35. Bendele, M. et al. Tuning the superconducting and magnetic properties of FeySe0.25Te0.75 by varying the iron content. Phys. Rev. B 82, 212504 (2010).

    Article  CAS  Google Scholar 

  36. Viennois, R., Giannini, E., van der Marel, D. & Cerny, R. Effect of Fe excess on structural, magnetic and superconducting properties of single-crystalline Fe1+xTe1−ySey. J. Solid State Chem. 183, 769–775 (2010).

    Article  CAS  Google Scholar 

  37. Dong, C. et al. Revised phase diagram for the FeTe1−xSex system with fewer excess Fe atoms. Phys. Rev. B 84, 224506 (2011).

    Article  CAS  Google Scholar 

  38. Sun, Y., Shi, Z. & Tamegai, T. Review of annealing effects and superconductivity in Fe1+yTe1−xSex superconductors. Supercond. Sci. Technol. 32, 103001 (2019).

    Article  CAS  Google Scholar 

  39. Wen, J., Xu, G., Gu, G., Tranquada, J. M. & Birgeneau, R. J. Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizations. Rep. Prog. Phys. 74, 124503 (2011).

    Article  CAS  Google Scholar 

  40. Tranquada, J. M., Xu, G. & Zaliznyak, I. A. Magnetism and superconductivity in Fe1+yTe1−xSex. J. Phys. Condens. Matter 32, 374003 (2020).

    Article  CAS  Google Scholar 

  41. Zaliznyak, I. A. et al. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS. J. Phys. Conf. Ser. 862, 012030 (2017).

    Article  CAS  Google Scholar 

  42. Rinott, S. et al. Tuning across the BCS-BEC crossover in the multiband superconductor Fe1+yTe1−xSex: an angle-resolved photoemission study. Sci. Adv. 3, e1602372 (2017).

    Article  CAS  Google Scholar 

  43. Zachar, O. & Zaliznyak, I. Dimensional cross-over and charge order in half-doped manganites and cobaltites. Phys. Rev. Lett. 91, 036401 (2003).

    Article  CAS  Google Scholar 

  44. Phillabaum, B., Carlson, E. W. & Dahmen, K. A. Spatial complexity due to bulk electronic nematicity in a superconducting underdoped cuprate. Nat. Commun. 3, 915 (2012).

    Article  CAS  Google Scholar 

  45. Witczak-Krempa, W., Chen, G., Kim, Y. B. & Balents, L. Correlated quantum phenomena in the strong spin-orbit regime. Annu. Rev. Condens. Matter Phys. 5, 57–82 (2014).

    Article  CAS  Google Scholar 

  46. Qiu, Y. et al. Spin gap and resonance at the nesting wave vector in superconducting FeSe0.4Te0.6. Phys. Rev. Lett. 103, 067008 (2009).

    Article  CAS  Google Scholar 

  47. Leiner, J. et al. Modified magnetism within the coherence volume of superconducting Fe1+δSexTe1−x. Phys. Rev. B 90, 100501 (2014).

    Article  CAS  Google Scholar 

  48. Xu, Z. et al. Disappearance of static magnetic order and evolution of spin fluctuations in Fe1+δSexTe1−x. Phys. Rev. B 82, 104525 (2010).

    Article  CAS  Google Scholar 

  49. Liu, X. et al. X-ray diffuse scattering study of local distortions in Fe1+xTe induced by excess Fe. Phys. Rev. B 83, 184523 (2011).

    Article  CAS  Google Scholar 

  50. Homes, C. C., Dai, Y. M., Schneeloch, J., Zhong, R. D. & Gu, G. D. Phonon anomalies in some iron telluride materials. Phys. Rev. B 93, 125135 (2016).

    Article  CAS  Google Scholar 

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Acknowledgements

We gratefully acknowledge discussions with M. Lumsden, A. Tsvelik, A. Balatsky, Q. Li and X. Wang, and technical assistance from F. Loeb and M. K. Graves-Brook. This work at the Brookhaven National Laboratory (BNL) was supported by the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, United States Department of Energy (US DOE), under contract no. DE-SC0012704. Work at BNL’s Center for Functional Nanomaterials was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US DOE, under the same contract. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.

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Authors and Affiliations

  1. Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA

    Yangmu Li, Nader Zaki, David Fobes, Zhijun Xu, Cedomir Petrovic, Genda Gu, Peter D. Johnson, John M. Tranquada & Igor A. Zaliznyak

  2. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA

    Vasile O. Garlea & Andrei T. Savici

  3. NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA

    Zhijun Xu

  4. Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA

    Zhijun Xu

  5. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA

    Fernando Camino

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Contributions

I.A.Z. conceived and directed the study. I.A.Z. and Y.L. designed the study with input from J.M.T. and P.D.J.; G.G., Z.X. and C.P. provided the samples for the study. I.A.Z., Y.L., D.F., A.T.S. and V.O.G. carried out neutron experiments and obtained the neutron data. N.Z. carried out ARPES measurements and initial ARPES analysis; Y.L. performed fitting of ARPES spectra. Y.L. performed local EDS and microprobe measurements with help from F.C. Y.L. and I.A.Z. analysed the data, prepared the figures and wrote the paper, with input from all authors.

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Correspondence to Igor A. Zaliznyak.

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Peer review Information Nature Materials thanks Donglai Feng and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–12 and discussion.

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Li, Y., Zaki, N., Garlea, V.O. et al. Electronic properties of the bulk and surface states of Fe1+yTe1−xSex. Nat. Mater. 20, 1221–1227 (2021). https://doi.org/10.1038/s41563-021-00984-7

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