Holes Localized on a Skyrmion in a Doped Antiferromagnet on the Honeycomb Lattice: Symmetry Analysis

TL;DR

This paper investigates how holes localize on Skyrmions in doped antiferromagnets on a honeycomb lattice, revealing unique localization properties and potential for f-wave pairing, differing from square lattice cases.

Contribution

It provides a symmetry analysis of hole localization on Skyrmions in honeycomb lattice antiferromagnets, highlighting differences from square lattice systems and implications for pairing symmetries.

Findings

Only holes in one momentum pocket localize on Skyrmions.

Magnon exchange favors f-wave pairing on the honeycomb lattice.

Quantum numbers of hole pairs suggest possible f-wave symmetry.

Abstract

Using the low-energy effective field theory for hole-doped antiferromagnets on the honeycomb lattice, we study the localization of holes on Skyrmions, as a potential mechanism for the preformation of Cooper pairs. In contrast to the square lattice case, for the standard radial profile of the Skyrmion on the honeycomb lattice, only holes residing in one of the two hole pockets can get localized. This differs qualitatively from hole pairs bound by magnon exchange, which is most attractive between holes residing in different momentum space pockets. On the honeycomb lattice, magnon exchange unambiguously leads to $f$-wave pairing, which is also observed experimentally. Using the collective-mode quantization of the Skyrmion, we determine the quantum numbers of the localized hole pairs. Again, $f$-wave symmetry is possible, but other competing pairing symmetries cannot be ruled out.