Skip to main content

Thank you for visiting 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.

Charge trapping and super-Poissonian noise centres in a cuprate superconductor


The electronic properties of cuprate high-temperature superconductors in their normal state are highly two-dimensional: transport along the crystal planes is perfectly metallic, but is insulating along the perpendicular ‘c-axis’ direction. The ratio of the in-plane to the perpendicular resistance can exceed 104 (refs 1,2,3,4). This anisotropy was identified as one of the mysteries of the cuprates early on5,6, and although widely different proposals exist for its microscopic origin7,8,9, there is little empirical information on the microscopic scale. Here, we elucidate the properties of the insulating layers with a newly developed scanning noise spectroscopy technique that can spatially map the current and its time-resolved fluctuations. We discover atomic-scale noise centres that exhibit megahertz current fluctuations 40 times the expectation from Poissonian noise, more than what has been observed in mesoscopic systems10. Such behaviour can happen only in highly polarizable insulators and represents strong evidence for trapping of charge in the charge reservoir layers. Our measurements suggest a picture of metallic layers separated by polarizable insulators within a three-dimensional superconducting state.

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

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Scanning tunnelling noise spectroscopy as a new diagnostic tool.
Fig. 2: Observation of super-Poissonian noise centres.
Fig. 3: Example of modulated transport by slow charge trapping processes.
Fig. 4: Bias-dependent conductance maps to identify impurity states and correlation with noise centres.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


  1. Watanabe, T., Fujii, T. & Matsuda, A. Anisotropic resistivities of precisely oxygen controlled single-crystal Bi2Sr2CaCu2O8+δ: Systematic study on ‘spin gap’ effect. Phys. Rev. Lett. 79, 2113–2116 (1997).

    Article  ADS  Google Scholar 

  2. Sordi, G., Sémon, P., Haule, K. & Tremblay, A. M. S. C-axis resistivity, pseudogap, superconductivity, and Widom line in doped Mott insulators. Phys. Rev. B 87, 041101(R) (2013).

    Article  ADS  Google Scholar 

  3. Levallois, J. et al. Temperature-dependent ellipsometry measurements of partial Coulomb energy in superconducting cuprates. Phys. Rev. X 6, 031027 (2016).

    Google Scholar 

  4. Kim, J. H. et al. Strong damping of the c-axis plasmon in high-T c cuprate superconductors. Physica C 247, 297–308 (1995).

    Article  ADS  Google Scholar 

  5. Anderson, P. W. Experimental constraints on the theory of high-T c superconductivity. Science 256, 1526–1531 (1992).

    Article  ADS  Google Scholar 

  6. Leggett, A. J. A. ‘midinfrared’ scenario for cuprate superconductivity. Proc. Natl Acad. Sci. USA 96, 8365–8372 (1999).

    Article  ADS  Google Scholar 

  7. Gutman, D. B. & Maslov, D. L. Anomalous c-axis transport in layered metals. Phys. Rev. Lett. 99, 196602 (2007).

    Article  ADS  Google Scholar 

  8. Johnston, S. et al. Systematic study of electron–phonon coupling to oxygen modes across the cuprates. Phys. Rev. B 82, 064513 (2010).

    Article  ADS  Google Scholar 

  9. Meevasana, W., Devereaux, T. P., Nagaosa, N., Shen, Z. X. & Zaanen, J. Calculation of overdamped c-axis charge dynamics and the coupling to polar phonons in cuprate superconductors. Phys. Rev. B 74, 174524 (2006).

    Article  ADS  Google Scholar 

  10. Blanter, Y. M. in CFN Lectures on Functional Nanostructures Vol. 2 (eds Vojta, M., Röthig, C. & Schön, G.) Ch. 3 (Springer, Berlin, Heidelberg, 2010)

  11. Anderson, P. W. & Zou, Z. ‘Normal’ tunneling and ‘normal’ transport: Diagnostics for the resonating-valence-bond state. Phys. Rev. Lett. 60, 132–135 (1988).

    Article  ADS  Google Scholar 

  12. Moses, P. & Mc Kenzie, R. H. Comparison of coherent and weakly incoherent transport models for the interlayer magnetoresistance of layered Fermi liquids. Phys. Rev. B 60, 7998–8011 (1999).

    Article  ADS  Google Scholar 

  13. Markiewicz, R. S., Sahrakorpi, S., Lindroos, M., Lin, H. & Bansil, A. One-band tight-binding model parametrization of the high-T c cuprates including the effect of k z dispersion. Phys. Rev. B 72, 54519 (2005).

    Article  ADS  Google Scholar 

  14. de-Picciotto, R. et al. Direct observation of a fractional charge. Nature 389, 162–164 (1997).

    Article  ADS  Google Scholar 

  15. Ronen, Y. et al. Charge of a quasiparticle in a superconductor. Proc. Natl Acad. Sci. USA 113, 1743–1748 (2016).

    Article  ADS  Google Scholar 

  16. van den Brom, H. & van Ruitenbeek, J. Quantum suppression of shot noise in atom-size metallic contacts. Phys. Rev. Lett. 82, 1526–1529 (1999).

    Article  ADS  Google Scholar 

  17. Blanter, Y. M. & Büttiker, M. Transition from sub-Poissonian to super-Poissonian shot noise in resonant quantum wells. Phys. Rev. B 59, 10217–10226 (1999).

    Article  ADS  Google Scholar 

  18. Birk, H., Jong, M., De & Schönenberger, C. Shot-noise suppression in the single-electron tunneling regime. Phys. Rev. Lett. 75, 1610–1613 (1995).

    Article  ADS  Google Scholar 

  19. Kemiktarak, U., Ndukum, T., Schwab, K. C. & Ekinci, K. L. Radio-frequency scanning tunnelling microscopy. Nature 450, 85–88 (2007).

    Article  ADS  Google Scholar 

  20. Burtzlaff, A., Schneider, N. L., Weismann, A. & Berndt, R. Shot noise from single atom contacts in a scanning tunneling microscope. Surf. Sci. 643, 10–12 (2016).

    Article  ADS  Google Scholar 

  21. Sung, M. G. et al. Scanning noise microscopy on graphene devices. ACS Nano 5, 8620–8628 (2011).

    Article  Google Scholar 

  22. DiCarlo, L. et al. System for measuring auto- and cross correlation of current noise at low temperatures. Rev. Sci. Instrum. 77, 073906 (2006).

    Article  ADS  Google Scholar 

  23. Keimer, B., Kivelson, S. A., Norman, M. R., Uchida, S. & Zaanen, J. From quantum matter to high-temperature superconductivity in copper oxides. Nature 518, 179–186 (2015).

    Article  ADS  Google Scholar 

  24. Carlson, E. W., Dahmen, K. A., Fradkin, E. & Kivelson, S. A. Hysteresis and noise from electronic nematicity in high-temperature superconductors. Phys. Rev. Lett. 96, 097003 (2006).

    Article  ADS  Google Scholar 

  25. Kivelson, S. A., Bindloss, I. P., Fradkin, E. & Oganesyan, V. How to detect fluctuating stripes in the high-temperature superconductors. Rev. Mod. Phys. 75, 1201–1241 (2003).

    Article  ADS  Google Scholar 

  26. Zhang, J. et al. Discovery of slow magnetic fluctuations and critical slowing down in the pseudogap phase of YBa2Cu3Oy. Sci. Adv. 4, 5235 (2018).

    Article  Google Scholar 

  27. Choubey, P., Kreisel, A., Berlijn, T., Andersen, B. M. & Hirschfeld, P. J. Universality of scanning tunneling microscopy in cuprate superconductors. Phys. Rev. B 96, 174523 (2017).

    Article  ADS  Google Scholar 

  28. Martin, I., Balatsky, A. V. & Zaanen, J. Impurity states and interlayer tunneling in high temperature superconductors. Phys. Rev. Lett. 88, 097003 (2002).

    Article  ADS  Google Scholar 

  29. Onac, E., Balestro, F., Trauzettel, B., Lodewijk, C. F. J. & Kouwenhoven, L. P. Shot-noise detection in a carbon nanotube quantum dot. Phys. Rev. Lett. 96, 026803 (2006).

    Article  ADS  Google Scholar 

  30. Thielmann, A., Hettler, M. H., Konig, J. & Schon, G. Cotunneling current and shot noise in quantum dots. Phys. Rev. Lett. 95, 146806 (2005).

    Article  ADS  Google Scholar 

  31. Safonov, S. S. et al. Enhanced shot noise in resonant tunneling via Interacting localized states. Phys. Rev. Lett. 91, 136801 (2003).

    Article  ADS  Google Scholar 

  32. Gustavsson, S. et al. Counting statistics and super-Poissonian noise in a quantum dot: Time-resolved measurements of electron transport. Phys. Rev. B 74, 195305 (2006).

    Article  ADS  Google Scholar 

  33. Zeljkovic, I. et al. Imaging the impact of single oxygen atoms on superconducting Bi2+ySr2−yCaCu2O8+x. Science 337, 320–323 (2012).

    Article  ADS  Google Scholar 

  34. Tsvetkov, A. A. et al. Global and local measures of the intrinsic Josephson coupling in Tl2Ba2CuO6 as a test of the interlayer tunneling model. Nature 395, 360–362 (1998).

    Article  ADS  Google Scholar 

  35. Reyen, N. et al. Superconducting interface between insulating oxides. Science 317, 1196–1199 (2007).

    Article  ADS  Google Scholar 

  36. Wang, Q. Y. et al. Interface-induced high-temperature superconductivity in single unit-cell FeSe films on SrTiO3. Chin. Phys. Lett. 29, 037402 (2012).

    Article  ADS  Google Scholar 

  37. Lee, J. J. et al. Interfacial mode coupling as the origin of the enhancement of T c in FeSe films on SrTiO3. Nature 515, 245–248 (2014).

    Article  ADS  Google Scholar 

  38. Kinoda, G. et al. Direct determination of localized impurity levels located in the blocking layers of Bi2Sr2CaCu2Oy using scanning tunneling microscopy/spectroscopy. Phys. Rev. B 71, 020502(R) (2005).

    Article  ADS  Google Scholar 

  39. Fei, Y. et al. Electronic effect of doped oxygen atoms in Bi2201 superconductors determined by scanning tunneling microscopy. Preprint at (2018).

  40. Dong, Q. et al. Ultra-low noise high electron mobility transistors for high-impedance and low-frequency deep cryogenic readout electronics. Appl. Phys. Lett. 105, 013504 (2014).

    Article  ADS  Google Scholar 

  41. Bastiaans, K. M. et al. Amplifier for scanning tunneling microscopy at MHz frequencies. Preprint at (2018).

Download references


We thank C. Beenakker, A. Ben Hamida, Y. Blanter, D. Chatzopoulos, V. Cheianov, T. Klapwijk, M. Leeuwenhoek and J. van Ruitenbeek for help and valuable discussions. This project was financially supported by the European Research Council (ERC StG SpinMelt) and by the Netherlands Organisation for Scientific Research (NWO/OCW), as part of the Frontiers of Nanoscience programme, as well as through a Vidi grant (680-47-536).

Author information

Authors and Affiliations



K.M.B, D.C., T.B, I.B. and M.P.A. designed, developed and performed the noise-spectroscopy STM experiments and analysed the data, Y.H. and M.S.G. created the samples, Q.D. and J.Y. constructed the HEMT. M.P.A. supervised the study. All authors contributed to the interpretation of the data.

Corresponding author

Correspondence to M. P. Allan.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary information

Supplementary Figures 1–9; Supplementary References 1–7

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Bastiaans, K.M., Cho, D., Benschop, T. et al. Charge trapping and super-Poissonian noise centres in a cuprate superconductor. Nature Phys 14, 1183–1187 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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