Quasiparticle excitations in frustrated antiferromagnets

TL;DR

This paper investigates how geometrical frustration in a triangular antiferromagnet affects quasiparticle excitations, revealing that frustration can break the conventional quasiparticle picture without requiring spin liquid phases.

Contribution

It introduces a detailed computation of quasiparticle wave functions considering multi-magnon effects in frustrated antiferromagnets, highlighting the impact of sign reversal of the hopping integral.

Findings

Sign reversal of hopping integral alters multi-magnon components.

Quasiparticle existence is sensitive to frustration-induced effects.

Conventional quasiparticle picture can be invalidated by geometrical frustration.

Abstract

We have computed the quasiparticle wave function corresponding to a hole injected in a triangular antiferromagnet. We have taken into account multi-magnon contributions within the self consistent Born approximation. We have found qualitative differences, under sign reversal of the integral transfer t, regarding the multi-magnon components and the own existence of the quasiparticle excitations. Such differences are due to the subtle interplay between magnon-assisted and free hopping mechanisms. We conclude that the conventional quasiparticle picture can be broken by geometrical frustration without invoking spin liquid phases.