New disordered anyon phase of doped graphene zigzag nanoribbon

TL;DR

This paper uncovers a novel disordered anyon phase in doped graphene zigzag nanoribbons, revealing fractional charges, spin-charge separation, and unique tunneling features, with potential experimental implications.

Contribution

It introduces a new disordered anyon phase in doped zigzag nanoribbons, characterized by fractional charges and distinctive edge states, using advanced numerical methods.

Findings

Fractional charges form a disordered anyon phase with edge spin density waves.

Sharp midgap peaks in tunneling density of states linked to fractional charges.

Midgap peak disappears at higher doping levels.

Abstract

We investigate interacting disordered zigzag nanoribbons at low doping, using the Hubbard model to treat electron interactions within the density matrix renormalization group and Hartree-Fock method. Extra electrons that are inserted into an interacting disordered zigzag nanoribbon divide into anyons. Furthermore, the fractional charges form a new disordered anyon phase with a highly distorted edge spin density wave, containing numerous localized magnetic moments residing on the zigzag edges, thereby displaying spin-charge separation and a strong non-local correlation between the opposite zigzag edges. We make the following new predictions, which can be experimentally tested: (1) In the low doping case and weak disorder regime, the soft gap in the tunneling density of states is replaced by a sharp peak at the midgap energy with two accompanying peaks. The $e^-/2$ fractional charges that reside on the boundary of the zigzag edges are responsible for these peaks. (2) We find that the midgap peak disappears as the doping concentration increases. The presence of $e-/2$ fractional charges will be strongly supported by the detection of these peaks. Doped zigzag ribbons may also exhibit unusual transport, magnetic, and inter-edge tunneling properties.