Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Nematic transitions in iron pnictide superconductors imaged with a quantum gas

Abstract

The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) uses an atomic Bose–Einstein condensate to measure magnetic fields emanating from solid-state samples. The quantum sensor does so with unprecedented d.c. sensitivity at micrometre resolution, from room to cryogenic temperatures1. An additional advantage of the SQCRAMscope is the preservation of optical access to the sample so that magnetometry imaging of, for example, electron transport may be performed in concert with other imaging techniques. Here, we apply this multimodal imaging capability to the study of nematicity in iron pnictide high-temperature superconductors, where the relationship between electronic and structural symmetry breaking resulting in a nematic phase is under debate2. We combine the SQCRAMscope with an in situ microscope that measures optical birefringence near the surface. This enables simultaneous and spatially resolved detection of both bulk and near-surface manifestations of nematicity via transport and structural deformation channels, respectively. By performing local measurements of emergent resistivity anisotropy in iron pnictides, we observe sharp, nearly concurrent transport and structural transitions. More broadly, these measurements demonstrate the SQCRAMscope’s ability to reveal important insights into the physics of complex quantum materials.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Multimodal SQCRAMscope.
Fig. 2: Optical birefringence, magnetometry and transport images.
Fig. 3: Temperature dependence of nematic order.
Fig. 4: Nematic transition temperatures.

Similar content being viewed by others

Data availability

The data represented in Figs. 2–4 are available as source data with the paper. All other data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

Code availability

The code supporting the figures and other findings of this study is available from the corresponding author upon request.

References

  1. Yang, F., Kollár, A. J., Taylor, S. F., Turner, R. W. & Lev, B. L. Scanning Quantum Cryogenic Atom Microscope. Phys. Rev. Appl. 7, 034026 (2017).

    Article  ADS  Google Scholar 

  2. Fernandes, R. M., Chubukov, A. V. & Schmalian, J. What drives nematic order in iron-based superconductors? Nat. Phys. 10, 97–104 (2014).

    Article  Google Scholar 

  3. Kivelson, S. A., Fradkin, E. & Emery, V. J. Electronic liquid-crystal phases of a doped Mott insulator. Nature 393, 550–553 (1998).

    Article  ADS  Google Scholar 

  4. Fradkin, E., Kivelson, S. A., Lawler, M. J., Eisenstein, J. P. & Mackenzie, A. P. Nematic Fermi fluids in condensed matter physics. Annu. Rev. Condens. Matter Phys. 1, 153–178 (2010).

    Article  ADS  Google Scholar 

  5. Lilly, M. P., Cooper, K. B., Eisenstein, J. P., Pfeiffer, L. N. & West, K. W. Evidence for an anisotropic state of two-dimensional electrons in high Landau levels. Phys. Rev. Lett. 82, 394–397 (1999).

    Article  ADS  Google Scholar 

  6. Borzi, R. A. et al. Formation of a nematic fluid at high fields in Sr3Ru2O7. Science 315, 214–217 (2007).

    Article  ADS  Google Scholar 

  7. Daou, R. et al. Broken rotational symmetry in the pseudogap phase of a high-T c superconductor. Nature 463, 519–522 (2010).

    Article  ADS  Google Scholar 

  8. Lawler, M. J. et al. Intra-unit-cell electronic nematicity of the high-T c copper-oxide pseudogap states. Nature 466, 347–351 (2010).

    Article  ADS  Google Scholar 

  9. Rotter, M. et al. Spin-density-wave anomaly at 140 K in the ternary iron arsenide BaFe2As2. Phys. Rev. B 78, 020503 (2008).

    Article  ADS  Google Scholar 

  10. Huang, Q. et al. Neutron-diffraction measurements of magnetic order and a structural transition in the parent BaFe2As2 compound of FeAs-based high-temperature superconductors. Phys. Rev. Lett. 101, 257003 (2008).

    Article  ADS  Google Scholar 

  11. Kim, M. G. et al. Character of the structural and magnetic phase transitions in the parent and electron-doped BaFe2As2 compounds. Phys. Rev. B 83, 134522 (2011).

    Article  ADS  Google Scholar 

  12. Chu, J.-H. et al. In-plane resistivity anisotropy in an underdoped iron arsenide superconductor. Science 329, 824–826 (2010).

    Article  ADS  Google Scholar 

  13. Tanatar, M. A. et al. Uniaxial-strain mechanical detwinning of CaFe2As2 and BaFe2As2 crystals: optical and transport study. Phys. Rev. B 81, 184508 (2010).

    Article  ADS  Google Scholar 

  14. Luo, X. et al. Antiferromagnetic and nematic phase transitions in BaFe2(As1-xPx)2 studied by ac microcalorimetry and SQUID magnetometry. Phys. Rev. B 91, 094512 (2015).

    Article  ADS  Google Scholar 

  15. Kuo, H.-H., Chu, J.-H., Palmstrom, J. C., Kivelson, S. A. & Fisher, I. R. Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors. Science 352, 958–962 (2016).

    Article  ADS  MathSciNet  Google Scholar 

  16. Fernandes, R. M., Fernandes, R. M. & Schmalian, J. Manifestations of nematic degrees of freedom in the magnetic, elastic, and superconducting properties of the iron pnictides. Supercond. Sci. Technol. 25, 084005 (2012).

    Article  ADS  Google Scholar 

  17. Tanatar, M. A. et al. Direct imaging of the structural domains in the iron pnictides AFe2As2(A = Ca, Sr, Ba). Phys. Rev. B 79, 180508 (2009).

    Article  ADS  Google Scholar 

  18. Thewalt, E. et al. Imaging anomalous nematic order and strain in optimally doped BaFe2(As,P)2. Phys. Rev. Lett. 121, 027001 (2018).

    Article  ADS  Google Scholar 

  19. Stojchevska, L., Mertelj, T., Chu, J. H., Fisher, I. R. & Mihailovic, D. Doping dependence of femtosecond quasiparticle relaxation dynamics in Ba(Fe,Co)2As2 single crystals: evidence for normal-state nematic fluctuations. Phys. Rev. B 86, 024519 (2012).

    Article  ADS  Google Scholar 

  20. Shimojima, T. et al. Pseudogap formation above the superconducting dome in iron pnictides. Phys. Rev. B 89, 045101 (2014).

    Article  ADS  Google Scholar 

  21. Sonobe, T. et al. Orbital-anisotropic electronic structure in the nonmagnetic state of BaFe2(As1−xPx)2 superconductors. Sci. Rep. 8, 2169 (2018).

    Article  ADS  Google Scholar 

  22. Yi, M. et al. Symmetry-breaking orbital anisotropy observed for detwinned Ba(Fe1−xCox)2As2 above the spin density wave transition. Proc. Natl Acad. Sci. USA 108, 6878–6883 (2011).

    Article  ADS  Google Scholar 

  23. Iye, T. et al. Emergence of orbital nematicity in the tetragonal phase of BaFe2(As1−xPx)2. J. Phys. Soc. Jpn 84, 043705 (2015).

    Article  ADS  Google Scholar 

  24. Kasahara, S. et al. Electronic nematicity above the structural and superconducting transition in BaFe2(As1−xPx)2. Nature 486, 382–385 (2012).

    Article  ADS  Google Scholar 

  25. Chu, J.-H., Analytis, J. G., Kucharczyk, C. & Fisher, I. R. Determination of the phase diagram of the electron-doped superconductor Ba(Fe1−xCox)2As2. Phys. Rev. B 79, 014506 (2009).

    Article  ADS  Google Scholar 

  26. Chu, J.-H., Kuo, H.-H., Analytis, J. G. & Fisher, I. R. Divergent nematic susceptibility in an iron arsenide superconductor. Science 337, 710–712 (2012).

    Article  ADS  Google Scholar 

  27. Binder, K. & Landau, D. Critical phenomena at surfaces. Physica A 163, 17–30 (1990).

    Article  ADS  Google Scholar 

  28. Brown, S. E., Fradkin, E. & Kivelson, S. A. Surface pinning of fluctuating charge order: an extraordinary surface phase transition. Phys. Rev. B 71, 224512 (2005).

    Article  ADS  Google Scholar 

  29. Song, K. W. & Koshelev, A. E. Surface nematic order in iron pnictides. Phys. Rev. B 94, 094509 (2016).

    Article  ADS  Google Scholar 

  30. Prozorov, R. et al. Intrinsic pinning on structural domains in underdoped single crystals of Ba(Fe1−xCox)2As2. Phys. Rev. B 80, 174517 (2009).

    Article  ADS  Google Scholar 

  31. Ishida, S. et al. Anisotropy of the in-plane resistivity of underdoped Ba(Fe1−xCox)2As2 superconductors induced by impurity scattering in the antiferromagnetic orthorhombic phase. Phys. Rev. Lett. 110, 207001 (2013).

    Article  ADS  Google Scholar 

  32. Ma, C. et al. Microstructure and tetragonal-to-orthorhombic phase transition of AFe2As2 (A = Sr, Ca) as seen via transmission electron microscopy. Phys. Rev. B 79, 060506 (2009).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank S. Kivelson for discussions and J.-H. Chu for early samples. We acknowledge funding support for apparatus construction from the US Office of Naval Research (ONR) (N00014-17-1-2248). Funding for F.Y. and partial support for S.D.E. were provided by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under award no. DE-SC0019174. Crystal growth and sample preparation were supported by the US Department of Energy, Office of Basic Energy Sciences, under contract no. DE-AC02-76SF00515. Fabrication of sample mount substrates and the atom chip were performed at the Stanford Nanofabrication Facility and the Stanford Nano Shared Facility, supported by the NSF under award no. ECCS-1542152. S.D.E. acknowledges partial support from the Karel Urbanek Postdoctoral Fellowship. S.F.T. and B.L.L. acknowledge support from the Gordon and Betty Moore Foundation through grant no. GBMF3502 and from the US Army Research Office (ARO) (W911NF1910392). J.C.P. acknowledges support from an NSF Graduate Research Fellowship (DGE-114747), a Gabilan Stanford Graduate Fellowship and the Gerald J. Lieberman Fellowship.

Author information

Authors and Affiliations

Authors

Contributions

J.C.P. and I.R.F. fabricated and characterized the samples. F.Y., S.F.T. and S.D.E. performed the experiments, and F.Y., S.F.T., S.D.E. and B.L.L. analysed the data. S.D.E., F.Y., S.F.T. and B.L.L. wrote the manuscript. B.L.L. and I.R.F. conceived the project, and B.L.L. supervised the project.

Corresponding author

Correspondence to Benjamin L. Lev.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Physics thanks Meng Khoon Tey and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Source data

Source Data Fig. 2

Representative optical birefringence, magnetometry and transport image data.

Source Data Fig. 3

Temperature dependence of nematic order in a wide temperature range.

Source Data Fig. 4

Temperature dependence of nematic order near the nematic phase transition.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yang, F., Taylor, S.F., Edkins, S.D. et al. Nematic transitions in iron pnictide superconductors imaged with a quantum gas. Nat. Phys. 16, 514–519 (2020). https://doi.org/10.1038/s41567-020-0826-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41567-020-0826-8

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing