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

K. M. Bastiaans, D. Cho, T. Benschop, I. Battisti, Y. Huang, M. S. Golden, Q. Dong, Y. Jin, J. Zaanen, M. P. Allan

Research output: Contribution to journalLetter

4 Citations (Scopus)

Abstract

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 10 4 (refs 1–4 ). This anisotropy was identified as one of the mysteries of the cuprates early on 5,6 , and although widely different proposals exist for its microscopic origin 7–9 , 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 systems 10 . 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.

Original languageEnglish
Pages (from-to)1183-1187
Number of pages5
JournalNature Physics
Volume14
Issue number12
DOIs
Publication statusPublished - 2018 Dec 1

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Bastiaans, K. M., Cho, D., Benschop, T., Battisti, I., Huang, Y., Golden, M. S., Dong, Q., Jin, Y., Zaanen, J., & Allan, M. P. (2018). Charge trapping and super-Poissonian noise centres in a cuprate superconductor. Nature Physics, 14(12), 1183-1187. https://doi.org/10.1038/s41567-018-0300-z