Effects of semiclassical spiral fluctuations on hole dynamics

TL;DR

This study explores how semiclassical spiral magnetic fluctuations influence hole dynamics in a square lattice antiferromagnet, revealing significant quasiparticle weight reduction and incoherent spectral functions in certain phases.

Contribution

It introduces a detailed analysis of hole behavior coupled to spiral fluctuations using exact diagonalization and self-consistent Born approximation, highlighting the impact of spiral pitch on spectral properties.

Findings

Strong reduction of quasiparticle weight in spiral phases

Spectral functions become incoherent with irregular peaks

Maximum scattering phase space at spiral pitch Q=(0.7,0.7)π

Abstract

We investigate the dynamics of a single hole coupled to the spiral fluctuations related to the magnetic ground states of the antiferromagnetic J_1-J_2-J_3 Heisenberg model on a square lattice. Using exact diagonalization on finite size clusters and the self consistent Born approximation in the thermodynamic limit we find, as a general feature, a strong reduction of the quasiparticle weight along the spiral phases of the magnetic phase diagram. For an important region of the Brillouin Zone the hole spectral functions are completely incoherent, whereas at low energies the spectral weight is redistributed on several irregular peaks. We find a characteristic value of the spiral pitch, Q=(0.7,0.7)\pi, for which the available phase space for hole scattering is maximum. We argue that this behavior is due to the non trivial interference of the magnon assisted and the free hopping mechanism for hole motion, characteristic of a hole coupled to semiclassical spiral fluctuations.