Doping dependent quasiparticle band structure in cuprate superconductors

TL;DR

This study uses exact diagonalization to analyze how hole doping alters the quasiparticle band structure in cuprate superconductors, revealing significant reconstructions near (pi,0) that align with experimental ARPES findings.

Contribution

It provides the first exact diagonalization analysis of doping effects on the quasiparticle band structure in the t-t'-t''-J model, highlighting the role of long-range hopping and spin correlations.

Findings

Doping causes a major reconstruction of the quasiparticle band near (pi,0).

Doped states near (pi,0) shift up to the Fermi level, creating flat bands.

Results agree with ARPES measurements on cuprate materials.

Abstract

We present an exact diagonalization study of the single particle spectral function in the so-called t-t'-t''-J model in 2D. As a key result, we find that unlike the `pure' t-J model, hole doping leads to a major reconstruction of the quasiparticle band structure near (pi,0): whereas for the undoped system the quasiparticle states near (pi,0) are deep below the top of the band at (pi/2,pi/2), hole doping shifts these states up to E_F, resulting in extended flat band regions close to E_F and around (pi,0). This strong doping-induced deformation can be directly compared to angle resolved photoemission results on Sr_2 Cu Cl_2 O_2, underdoped Bi2212 and optimally doped Bi2212. We propose the interplay of long range hopping and decreasing spin correlations as the mechanism of this deformation.