Coexistence of Superconducting and Charge orders in IrTe2 nanoflakes

IrTe$_2$ holds a unique position in transition metal dichalcogenides (TMDCs) because of its intriguing correlated electronic phases including stripe charge/orbital order [1] and metastable superconductivity [2,3]. In bulk IrTe$_2$ crystals with chemical doping or thermal quenching, the superconducting order competes with the stripe order, which has supported a prevalent scenario that fluctuations or partial melting of a parent order are essential for inducing or enhancing superconductivity, as found in many unconventional superconductors. In this talk, we present a contrary example [4], found in IrTe$_2$ 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 IrTe$_2$ nanoflakes significantly increases the out-of-plane coherence length and the coupling strength of superconductivity, in contrast to the doped bulk IrTe$_2$. These findings clarify that the inherent instabilities of the parent stripe phase are sufficient to induce superconductivity in IrTe$_2$ without its complete or partial melting.

[1] M. J. Eom $\textit{et al.}$, PRL 113, 266406 (2014).
[2] M. Yohida $\textit{et al.}$, Nano Lett. 18, 3113 (2016).
[3] H. Oike $\textit{et al.}$, Sci. Adv. 4, (2018).
[4] S. Park $\textit{et al.}$, Nat. Commun. 12, 3157 (2021).