Charge correlations and optical conductivity in weakly doped antiferromagnets

Abstract

We investigate the dynamical charge-charge correlation function and the optical conductivity in weakly doped antiferromagnets using Mori-Zwanzig projection technique. The system is described by the two-dimensional t-J model. The arising matrix elements are evaluated within a cumulant formalism which was recently applied to investigate magnetic properties of weakly doped antiferromagnets. Within the present approach the ground state consists of non-interacting hole quasiparticles. Our spectra agree well with numerical results calculated via exact diagonalization techniques. The method we employ enables us to explain the features present in the correlation functions. We conclude that the charge dynamics at weak doping is governed by transitions between excited states of spin-bag quasiparticles.

5 pages, 2 figures, to appear in Europhys. Letters

References in corpus (8)

• Correlated Electrons in High Temperature Superconductors
• Antiferromagnetic and van Hove Scenarios for the Cuprates: Taking the Best of Both Worlds
• Anomalous Spin and Charge Dynamics of the 2D t-J Model at low doping
• Theory of the density fluctuation spectrum of strongly correlated electrons
• Charge Dynamics in the Planar t-J Model
• Statics and dynamics of charge fluctuations in the t-J model
• Cumulant approach to weakly doped antiferromagnets
• Optical conductivity of strongly correlated electron systems

Cited by in corpus (4)

• Self-energy and Fermi surface of the 2-dimensional Hubbard model
• Spin-polaron band structure and hole pockets in underdoped cuprates
• Optical conductivity due to orbital polarons in systems with orbital degeneracy
• Theory of the Lightly Doped Mott Insulator