Superconductivity emerging from a stripe charge order in IrTe2 nanoflakes

TL;DR

This study reveals that in IrTe2 nanoflakes, superconductivity arises within the stripe charge order phase, challenging the common view that superconductivity emerges from melting of the parent order, and highlights thickness control as a key tool.

Contribution

It demonstrates that inherent stripe charge order in IrTe2 nanoflakes can induce superconductivity without melting, contrasting with bulk behavior and emphasizing the role of thickness control.

Findings

Superconductivity coexists with stripe charge order in IrTe2 nanoflakes.

Thickness-dependent phase diagram shows superconductivity inside the parent charge order phase.

Increased out-of-plane coherence length and coupling strength due to stripe order.

Abstract

Superconductivity in the vicinity of a competing electronic order often manifests itself with a superconducting dome, centred at a presumed quantum critical point in the phase diagram. This common feature, found in many unconventional superconductors, has supported a prevalent scenario that fluctuations or partial melting of a parent order are essential for inducing or enhancing superconductivity. Here we present a contrary example, found in IrTe2 nanoflakes of which the superconducting dome is identified well inside the parent stripe charge ordering phase in the thickness-dependent phase diagram. The coexisting stripe charge order in IrTe2 nanoflakes significantly increases the out-of-plane coherence length and the coupling strength of superconductivity, in contrast to the doped bulk IrTe2. These findings clarify that the inherent instabilities of the parent stripe phaseare sufficient to induce superconductivity in IrTe2 without its complete or partial melting. Our study highlights the thickness control as an effective means to unveil intrinsic phase diagrams of correlated vdW materials.