A unified form of low-energy nodal electronic interactions in hole-doped cuprate superconductors

T J Reber,Q Wang,N C Plumb,J A Waugh,D S Dessau,H Eisaki,J S Wen,Y Cao,Z J Xu,X Zhou,H Li,G Gu,S Parham,Z Sun,G B Arnold,Y Yoshida

doi:10.1038/s41467-019-13497-4

Abstract

Using angle resolved photoemission spectroscopy measurements of Bi2Sr2CaCu2O8+δ over a wide range of doping levels, we present a universal form for the non-Fermi liquid electronic interactions in the nodal direction in the exotic normal state phase. It is described by a continuously varying power law exponent versus energy and temperature (hence named a Power Law Liquid or PLL), which with doping varies smoothly from a quadratic Fermi Liquid in the overdoped regime, to a linear Marginal Fermi Liquid at optimal doping, to a non-quasiparticle non-Fermi Liquid in the underdoped regime. The coupling strength is essentially constant across all regimes and is consistent with Planckian dissipation. Using the extracted PLL parameters we reproduce the experimental optics and resistivity over a wide range of doping and normal-state temperature values, including the T* pseudogap temperature scale observed in the resistivity curves. This breaks the direct link to the pseudogapping of antinodal spectral weight observed at similar temperature scales and gives an alternative direction for searches of the microscopic mechanism.

Highlights

Using angle resolved photoemission spectroscopy measurements of Bi2Sr2CaCu2O8+δ over a wide range of doping levels, we present a universal form for the non-Fermi liquid electronic interactions in the nodal direction in the exotic normal state phase
This linear-in-T strange metal behavior is considered so unusual that it is believed by many to signal a new state of matter, motivating many of the most influential and exotic theoretical ideas of the cuprate problem including Anderson’s resonating valence bond (RVB)[4], the marginal Fermi liquid (MFL)[5], many ideas about quantum critical points[6,7] as well as duals of string-theory models of quantum gravity[8]
To the far right at high doping levels a regular Fermi liquid exists, while to the left at low doping levels is an unusual and poorly understood pseudogap state in which there is an incomplete suppression of low-energy spectral weight, especially at the antinodal regime of the Brillouin zone

Summary

Results and discussion

Ð1Þ where Σ′′(ω) is the imaginary part of the self-energy directly measured in our experiment, Γ0 is an offset parameter accounting for impurity or disorder scattering, λ is a coupling parameter indicating the overall strength of the scattering, ωN is a normalization frequency whose exponent maintains the proper dimensionality of the self-energy, parameter β governs the comparative strengths of temperature and energy, and α is the critical PLL variable that takes the system from a FL to a MFL, and beyond Note that this formalism does not directly contain any low energy scales that would be associated with superconductivity, the pseudogap, phonons, or other bosonic modes. We believe it is likely that there are multiple contributions to the nodal kink —(a) the boson effect that is observed below Tc, and which might

Doping level

Fermi liquid limit b

Author contributions

Additional information