Possible Electronic Structure of Domain Walls in Mott Insulators

TL;DR

This paper explores the quantum structure of domain walls in doped Mott insulators, proposing a minimal wall hypothesis that links observed structures with doping levels and may explain anomalies in cuprate superconductors.

Contribution

It introduces a minimal wall hypothesis for domain walls in doped Mott insulators, connecting spatial structures with doping and bulk order types, and discusses its relevance to cuprate anomalies.

Findings

Minimal wall hypothesis correlates domain wall structure with doping level.

Domain walls can be supported by both antiferromagnetic and orbital antiferromagnetic order.

Hypothesis plausibly explains anomalous features of cuprate high-temperature superconductors.

Abstract

We discuss the quantum numbers of domain walls of minimal length induced by doping Mott insulators, carefully distinguishing between holon and hole walls. We define a minimal wall hypothesis that uniquely correlates the observed spatial structure with the doping level for the low-temperature commensurate insulating state of La$_{2-x}$Ba$_x$CuO$_4$ and related materials at $x={1\over 8}$. We remark that interesting walls can be supported not only by conventional antiferromagnetic but also by orbital antiferromagnetic (staggered flux phase, $d$-density) bulk order. We speculate on the validity of the minimal wall hypothesis more generally, and argue that it plausibly explains several of the most striking anomalous features of the cuprate high-temperature superconductors.