Oxide Fermi liquid universality revealed by electron spectroscopy

Abstract

We present a combined soft x-ray and high-resolution vacuum-ultraviolet angle-resolved photoemission spectroscopy study of the electron-overdoped cuprate Pr 1.3−x La 0.7 Ce x CuO 4 (PLCCO). Demonstration of its highly two-dimensional band structure enabled precise determination of the in-plane self-energy dominated by electron-electron scattering. Through analysis of this self-energy and the Fermi liquid cut-off energy scale, we find-in contrast to hole-doped cuprates-a momentum isotropic and comparatively weak electron correlation in PLCCO. Yet, the self-energies extracted from multiple oxide systems combine to demonstrate a logarithmic divergent relation between the quasiparticle scattering rate and mass. This constitutes a spectroscopic version of the Kadowaki-Woods relation with an important merit-the demonstration of Fermi liquid quasiparticle lifetime and mass being set by a single energy scale.

Resilient Fermi liquid and strength of correlations near an antiferromagnetic quantum critical point

“…Note that for a given threshold, all dopings of the left panel here fall on the same straight line, with only small variations. a 2 coefficient in the electron-doped cuprate PLCCO is constant as a function of the Fermi-surface angle in the overdoped regime [8]. These measurements are reminiscent of our results at x = 0.25, far from the AFM QCP.…”

“…Horio et al [8] also suggested a spectroscopic analog of the Kadowaki-Woods ratio that would relate a 2 and Z, two quantities we obtained in our calculations for multiple values of U . This is discussed in Fig.…”

“…Detailed analysis of the Fermi surface quasiparticles through the extraction of the self-energy from ARPES measurements have been performed on multiple materials, such as Sr 2 RuO 4 [4], organic metals [5], the hole-doped cuprates Bi 2 Sr 2 CaCu 2 O 8 and La 2−x Sr x CuO 4 [6,7] and the electrondoped cuprate PLCCO [8]. In all these cases, Fermi-liquid quasiparticles have been shown to persist in some segments of the Fermi surface, especially away from putative QCPs in overdoped samples.…”

“…where T is temperature, ω is frequency, and ω c is a cutoff frequency. The parameters a 2 , a 0 and ω c can be extracted from ARPES measurements [7,8]. In general, the self-energy is momentum-dependent, even though we do not write it explicitly.…”

“…Fermi liquid and strength of interactions.-The properties of the antinodal Fermi liquid can be used to quantify the strength of interactions. It has been proposed that the Fermiliquid cutoff frequency ω c , namely the frequency at which ω 2 behaviour disappears, can indicate the strength of the interactions in a correlated material [8]. We focus on the antinodal direction for x = 0.15, x = 0.20 and x = 0.25, and on the nodal direction for x = 0.25, where the Fermi liquid is stable.…”