Thinning-Induced Metastable Superconductivity in a Correlated 2D Material: 1T-IrTe2

Recently, reduced thickness was found to dramatically impact not only the static electronic structure (e.g. graphene, MoS2), but also the dynamic ordering kinetics (e.g. 1T-TaS2) [1]. The ordering kinetics of first-order phase transitions becomes significantly slowed with decreasing thickness, and metastable supercooled states can be realized by thinning alone. We therefore focus on layered iridium ditelluride (IrTe2), a charge-ordering system that is transformed into a superconductor by suppressing its first-order transition. Here, we discovered a persistent superconducting zero-resistance state in mechanically-exfoliated IrTe2 thin flakes [2]. The maximum superconducting critical temperature was identical to that of the bulk crystal which is chemically optimized, and the emergent superconductivity was revealed to have a metastable nature. The discovered robust metastable superconductivity suggests that 2D material is a new platform to induce, control, and functionalize metastable electronic states that are inaccessible in bulk crystals. [1. M. Yoshida et al. Sci. Adv. 1, e1500606 (2015); 2. M. Yoshida et al., Nano Lett. 18, 3113 (2018)]