The Fermi surface of underdoped high-T_c superconducting cuprates

TL;DR

This paper investigates the electronic structure of underdoped high-T_c cuprates, revealing a d-wave pseudogap and a half-pocket Fermi surface consistent with experimental ARPES data, using a slave boson theoretical approach.

Contribution

It introduces a model combining $$-flux and d-wave RVB states, predicting a doping-dependent Fermi surface and pseudogap features in underdoped cuprates.

Findings

Identification of a critical doping level $_c$ for state stability.

Calculation of a pseudogap with d-wave symmetry.

Observation of a half-pocket Fermi surface in the spectral function.

Abstract

The coexistence of $\pi$-flux state and d-wave RVB state is considered in this paper within the slave boson approach. A critical value of doping concentration $\delta_c$ is found, below which the coexisting $\pi$-flux and d-wave RVB state is favored in energy. The pseudo Fermi surface of spinons and the physical electron spectral function are calculated. A clear Fermi-level crossing is found along the (0,0) to ($\pi$, $\pi$) direction, but no such crossing is detected along the ($\pi$, 0) to ($\pi$, $\pi$) direction. Also, an energy gap of d-wave symmetry appears at the Fermi level in our calculation. The above results are in agreement with the angle-resolved photoemission experiments which indicate at a d-wave pseudo-gap and a half-pocket-like Fermi surface in underdoped cuprates.