Pressure tuning of light-induced superconductivity in K3C60

TL;DR

This study demonstrates that applying hydrostatic pressure suppresses light-induced superconductivity in K3C60, indicating a close link to equilibrium phases and suggesting potential room-temperature transient superconductivity.

Contribution

It reveals how pressure tuning affects light-induced superconductivity in K3C60, providing insights into its mechanisms and ruling out metallic phase explanations.

Findings

Superconductivity disappears around 0.3 GPa pressure.

Pressure dependence links transient and equilibrium superconducting states.

Transient superconductivity may exist near room temperature.

Abstract

Optical excitation at terahertz frequencies has emerged as an effective means to manipulate complex solids dynamically. In the molecular solid K3C60, coherent excitation of intramolecular vibrations was shown to transform the high temperature metal into a non-equilibrium state with the optical conductivity of a superconductor. Here we tune this effect with hydrostatic pressure, and we find it to disappear around 0.3 GPa. Reduction with pressure underscores the similarity with the equilibrium superconducting phase of K3C60, in which a larger electronic bandwidth is detrimental for pairing. Crucially, our observation excludes alternative interpretations based on a high-mobility metallic phase. The pressure dependence also suggests that transient, incipient superconductivity occurs far above the 150 K hypothesised previously, and rather extends all the way to room temperature.