Termination-Controlled Fractionalization and Hybridization at Topological Interfaces in Organic Spin Chains

TL;DR

This paper explores how termination parity controls fractional modes at topological interfaces in organic spin chains, enabling the engineering of boundary states through hybridization and domain design.

Contribution

It introduces a novel mechanism where termination parity governs fractional boundary modes, providing a new design principle for topological spin chain interfaces.

Findings

Termination parity controls fractional mode quenching or release.

Hybridization of boundary modes exhibits exponential decay with domain size.

Termination parity can be used to engineer and couple fractional boundary states.

Abstract

A single organic spin platform hosts both dimerized $S=\tfrac{1}{2}$ and effective Haldane $S=1$ sectors, linked by bond-texture inversion. At the junction, the fractional mode is controlled by termination parity: quenched by local fusion at one termination and released as an uncompensated spin-$\tfrac{1}{2}$-like degree of freedom at the parity-shifted one. Two such internal boundary modes of a finite embedded Haldane domain hybridize with an exponentially decaying splitting, establishing termination parity as a design principle for engineering and coupling fractional boundary modes.