Hierarchical stripe phases in IrTe2 driven by competition between Ir dimerization and Te bonding

TL;DR

This study reveals that the complex stripe phases in IrTe2 are driven by competing Ir dimerization and Te bonding, leading to a hierarchical phase diagram similar to the devil's staircase phenomenon.

Contribution

It provides atomic-scale evidence that the ground state is a q=1/6 stripe phase and elucidates the competition between Ir-Ir dimerization and Te-Te bonding as the origin of multiple phases.

Findings

Ground state is a q=1/6 stripe phase.

Multiple transitions driven by Ir-Ir dimerization.

Hierarchical phase diagram resembling devil's staircase.

Abstract

Layered 5d transition metal dichalcogenide (TMD) IrTe2 is distinguished from the traditional TMDs (such as NbSe2) by the existence of multiple CDW-like stripe phases and superconductivity at low temperatures. Despite of intensive studies, there is still no consensus on the physical origin of the stripe phases or even the ground state modulation for this 5d material. Here, we present atomic-scale evidence from scanning tunneling microscopy and spectroscopy (STM/STS), that the ground state of IrTe2 is a q=1/6 stripe phase, identical to that of the Se-doped compound. Furthermore, our data suggest that the multiple transitions and stripe phases are driven by the intralayer Ir-Ir dimerization that competes against the interlayer Te-Te bonding. The competition results in a unified phase diagram with a series of hierarchical modulated stripe phases, strikingly similar to the renowned "devil's staircase" phenomena.