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Open Access Publications from the University of California

Three interaction energy scales in the single-layer high- Tc cuprate HgBa2Cu O4+δ

  • Author(s): Sreedhar, SA
  • Rossi, A
  • Nayak, J
  • Anderson, ZW
  • Tang, Y
  • Gregory, B
  • Hashimoto, M
  • Lu, DH
  • Rotenberg, E
  • Birgeneau, RJ
  • Greven, M
  • Yi, M
  • Vishik, IM
  • et al.

© 2020 American Physical Society. The lamellar cuprate superconductors exhibit the highest ambient-pressure superconducting transition temperatures (Tc), and after more than three decades of extraordinary research activity, continue to pose formidable scientific challenges. A major experimental obstacle has been to distinguish universal phenomena from materials- or technique-dependent ones. Angle-resolved photoemission spectroscopy (ARPES) measures momentum-dependent single-particle electronic excitations and has been invaluable in the endeavor to determine the anisotropic momentum-space properties of the cuprates. HgBa2CuO4+δ (Hg1201) is a single-CuO2-layer cuprate with a particularly high optimal Tc and a simple crystal structure, yet there exists little information from ARPES about the electronic properties of this model system. Here we present an ARPES study of doping-, temperature-, and momentum-dependent systematics of near-nodal dispersion anomalies in Hg1201. The data reveal a hierarchy of three distinct energy scales: a subgap low-energy kink, an intermediate-energy kink near 55 meV, and a peak-dip-hump structure. The first two features are attributed to the coupling of electrons to Ba-derived optical phonons and in-plane bond-stretching phonons, respectively. The nodal peak-dip-hump structure appears to have a common doping dependence in several single-layer cuprates and is interpreted as a manifestation of pseudogap physics at the node. These results establish several universal phenomena, both in terms of connecting multiple experimental techniques for a single material and in terms of connecting comparable spectral features in multiple structurally similar cuprates.

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