Microscopic evidence for the intra-unit-cell electronic nematicity inside the pseudogap phase in YBa2Cu4O8

Wen Wang, Jun Luo, Chun Guang Wang, Jie Yang, Yasuharu Kodama, Rui Zhou, Guo Qing Zheng

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9 Citations (Scopus)


Understanding the nature of the mysterious pseudogap phenomenon is one of the most important issues associated with cuprate high-Tc superconductors. Here, we report 17O nuclear magnetic resonance (NMR) studies on two planar oxygen sites in stoichiometric cuprate YBa2Cu4O8 to investigate the symmetry breaking inside the pseudogap phase. We observe that the Knight shifts of the two oxygen sites are identical at high temperatures but different below Tnem ∼ 185 K, which is close to the pseudogap temperature T*. Our result provides a microscopic evidence for intra-unit-cell electronic nematicity. The difference in quadrupole resonance frequency between the two oxygen sites is unchanged below Tnem, which suggests that the observed nematicity does not directly stem from the local charge density modulation. Furthermore, a short-range charge density wave (CDW) order is observed below T ≃ 150 K. The additional broadening in the 17O-NMR spectra because of this CDW order is determined to be inequivalent for the two oxygen sites, which is similar to that observed in case of nematicity. These results suggest a possible connection between nematicity, CDW order, and pseudogap.

Original languageEnglish
Article number237413
JournalScience China: Physics, Mechanics and Astronomy
Issue number3
Publication statusPublished - Mar 2021


  • high-temperature superconductors
  • nematic order
  • nuclear magnetic resonance
  • pseudogap

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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