Anisotropic suppression of quasiparticle weight in two-dimensional electron system with partially flat Fermi surface: two-loop renormalization-group analysis

TL;DR

This study uses two-loop renormalization-group analysis to show that in a two-dimensional electron system with a partially flat Fermi surface, quasiparticle weight is anisotropically suppressed, aligning with experimental pseudogap observations.

Contribution

It provides a two-loop RG analysis revealing anisotropic quasiparticle suppression in flat Fermi surface regions, independent of pairing mechanisms.

Findings

Quasiparticle weight is anisotropically suppressed in flat Fermi surface regions.

Suppression is strongest at the center of flat regions as energy decreases.

Results qualitatively match angle-resolved photoemission spectroscopy data for underdoped cuprates.

Abstract

Two-loop renormalization-group analysis for a two-dimensional electron system with a partially flat Fermi surface has been carried out. We found that, {\it irrespective of pairing mechanism}, the quasiparticle weight is anisotropically suppressed due to logarithmically singular processes in the flat regions of the Fermi surface. When the energy scale decreases, the quasiparticle weight is the most strongly suppressed around the center of the flat region, which qualitatively agrees with the anisotropic pseudogap behavior suggested through the angle-resolved photoemission spectroscopy experiments for underdoped Bi$_2$Sr$_2$CaCu$_2$O$_8$.