Luttinger liquid phenomenology and angle resolved photoemission for single layer $\chem{Bi_2Sr_{2-x}La_xCuO_{6+\delta}}$ high--temperature superconductor

TL;DR

This paper interprets ARPES splitting in a high-temperature superconductor using a phenomenological Luttinger-liquid model, highlighting momentum-dependent parameters and the role of scattering in the spectral background.

Contribution

It introduces a Luttinger-liquid phenomenological framework with momentum-dependent parameters to explain ARPES features in a high-Tc superconductor, extending beyond one-dimensional models.

Findings

The spectral function fits well with ARPES data along the $ ext{Γ-M}$ line.

Both the scaling exponent and spin-charge separation parameter are momentum dependent.

High-energy spectra involve additional scattering processes leading to incoherent background.

Abstract

Recently observed splitting in angular resolved photoemission spectroscopy (ARPES) on $\chem{Bi_2Sr_{2-x}La_xCuO_{6+\delta}}$ high--temperature superconductor (Janowitz C. {\it et al.}, {\it Europhys. Lett.}, {\bf 60} (2002) 615) is interpreted within the phenomenological Luttinger--liquid framework, in which both the non--Fermi liquid scaling exponent of the spectral function and the spin--charge separation are introduced. The anomalous Green function with adjustable parameters fits very well to the Fermi edge and the low--energy part of ARPES along the $\Gamma-M$ line in the Brillouin zone. In contrast to one--dimensional models with Luttinger--liquid behavior we find that both the anomalous scaling $\alpha$ and the parameter $\delta$ describing the spin--charge separation are momentum dependent. The higher--energy part of the spectra is not accounted for by this simple Luttinger--liquid form of the Green function. In this energy regime additional scattering processes are plausible to produce the experimentally observed wide incoherent background, which diminishes as the inverse of the energy.