Hole-pair hopping in arrangements of hole-rich/hole-poor domains in a quantum antiferromagnet

TL;DR

This study reveals that in doped quantum antiferromagnets with stripe-like domains, bound hole pairs preferentially hop between hole-rich regions at around 100 K, potentially leading to superfluidity of these pairs.

Contribution

It demonstrates that antiferromagnetic hole-poor domains act as a filter favoring the exchange of bound hole pairs, a novel mechanism influencing superconductivity in cuprates.

Findings

Bound hole pairs hop more readily than single holes at ~100 K.

Hole-rich domains facilitate the formation of a superfluid of bound pairs.

Antiferromagnetic domains serve as a filter for hole pair exchange.

Abstract

We study the motion of holes in a doped quantum antiferromagnet in the presence of arrangements of hole-rich and hole-poor domains such as the stripe-phase in high-$T_C$ cuprates. When these structures form, it becomes energetically favorable for single holes, pairs of holes or small bound-hole clusters to hop from one hole-rich domain to another due to quantum fluctuations. However, we find that at temperature of approximately 100 K, the probability for bound hole-pair exchange between neighboring hole-rich regions in the stripe phase, is one or two orders of magnitude larger than single-hole or multi-hole droplet exchange. As a result holes in a given hole-rich domain penetrate further into the antiferromagnetically aligned domains when they do it in pairs. At temperature of about 100 K and below bound pairs of holes hop from one hole-rich domain to another with high probability. Therefore our main finding is that the presence of the antiferromagnetic hole-poor domains act as a filter which selects, from the hole-rich domains (where holes form a self-bound liquid), hole pairs which can be exchanged throughout the system. This fluid of bound hole pairs can undergo a superfluid phase ordering at the above mentioned temperature scale.