Fermi Surface Evolution, Pseudo Gap and Stagger Gauge Field Fluctuation in Underdoped Cuprates

TL;DR

This paper investigates how staggered gauge field fluctuations influence the Fermi surface evolution and spectral functions in underdoped cuprates, providing theoretical insights consistent with ARPES experimental observations.

Contribution

It introduces the role of staggered gauge field fluctuations in the t-J model to explain Fermi surface changes and spectral line shapes in underdoped cuprates, a novel aspect not previously emphasized.

Findings

Spectral function near (π,0) broad in underdoped, sharp in overdoped cases.

Quasiparticle peaks near (0.5π,0.5π) are sharp in both doping regimes.

Fermi surface crossover from small segments to large continuous surface explained by gauge fluctuations.

Abstract

In the context of t-J model we show that in underdoped regime,beside the usual long wave length gauge field fluctuation, an additional low energy fluctuation, staggered gauge field fluctuation plays a crucial role in the evolution of Fermi surface(FS) as well as the line shape of spectral function for the cuprates. By including the staggered gauge field fluctuation we calculate the spectral function of the electrons by RPA(random phase approximation). The line shape of the spectral function near $(\pi,0)$ is very broad in underdoped case and is quite sharp in overdoped case. For the spectral function near $(0.5\pi,0.5\pi)$, the quasiparticle peaks are always very sharp in both underdoped and overdoped case. The temperature dependence of the spectral function is also discussed in our present calculation. These results fit well with the recent ARPES experiments. We also calculate the FS crossover from a small four segment like FS to a large continuous FS. The reason of such kind of FS crossover is ascribed to the staggered gauge field fluctuation which is strong in underdoped regime and becomes much weaker in overdoped regime. The pseudo gap extracted from the ARPES data can be also interpreted by the calculation.