Honeycomb Charge Ordering in IrTe$_2$

TL;DR

This study reveals a unique honeycomb charge order in IrTe$_2$, observed via STM/STS, coexisting with stripe phases, and proposes it as a pathway to exotic Dirac electron systems.

Contribution

It uncovers a novel honeycomb charge ordering in IrTe$_2$ and models its formation from stripe orders, suggesting potential for exotic electronic states.

Findings

Honeycomb charge order observed on IrTe$_2$ surface.

Honeycomb phase coexists with stripe charge order.

Model based on overlap of three stripe orders.

Abstract

We report on the observation of a unique honeycomb charge ordering of the cleaved IrTe$_2$ surface by high-resolution scanning tunneling microscopy (STM) and spectroscopy (STS). IrTe$_2$ was recently established to exhibit intriguing stripe charge orderings. Here, we show that the stripe charge order coexists with a metastable honeycomb phase formed locally. The atomic and electronic structures of the honeycomb phase are consistent with the stripe phase indicating unambiguously its charge order nature. A simple model of the honeycomb structure is suggested based on the overlap of three degenerate stripe orders, which is analogous to the 3$q$ state description of a skyrmion. We suggest that the honeycomb charge order can be a route to an exotic Dirac electron system.