Momentum dependent relaxation rate and pseudogap in doped magnetic insulators

TL;DR

This study investigates the spectral functions and self energies in doped magnetic insulators using the t-t'-J model, revealing a pseudogap and momentum-dependent relaxation rates consistent with experimental observations.

Contribution

It provides a detailed analysis of the pseudogap and relaxation rates in doped cuprates using exact diagonalization, highlighting the momentum and doping dependence of these phenomena.

Findings

Truncated Fermi surface at low doping and negative t' in the antinodal region.

Weakly k- and doping-dependent anomalous relaxation rate |''(k,)|~ a+b|| for <0.

Pronounced pseudogap component with Lorentzian form at low doping.

Abstract

The spectral functions and corresponding self energies are calculated within the planar t-t'-J model as relevant to hole-doped cuprates using the exact diagonalization method at finite temperatures, combined with the averaging over twisted boundary conditions. Results show truncated Fermi surface at low doping and t'<0 in the antinodal region while the self energy reveals weakly k- and doping dependent anomalous relaxation rate |\Sigma''(k,\omega)|~ a+b|\omega| for \omega<0, consistent with recent ARPES results, and a pseudogap-generating component of Lorentzian form. The latter is well pronounced at low doping and strongly depends on k and t'.