부산대학교 도서관

Illumination of light on matter normally causes heating and destroys the ordered ground states. Despite this common understanding, recent advances in ultrafast light sources have enabled the non-thermal control of quantum phases. Here, we report the light-induced enhancement of superconductivity in a thin film of an iron chalcogenide FeSe0.5Te0.5, which exhibits multiple quantum condensates associated with the multi-orbital character. Upon the photoexcitation, we observed a transient increase of the superfluid density as indicated by the optical conductivity in the frequency range of superconducting gaps. The light-induced enhancement of superconductivity is further corroborated by the photoinduced enhancement of terahertz third harmonic generation, which is accounted for by the Higgs mode response. The ultrafast dynamics of two superfluid components revealed by frequency- and time-resolved terahertz measurements indicate the interplay between the condensates through the interband Cooper pairings while suggesting the potential tunability of the pairing interaction by light in the ultrafast timescale. Light-matter interaction is not only used to melt electronic orders, but also carry the potential as a non-thermal tuning knob to enhance emergent orders. Here the authors demonstrate a light-induced transient enhancement of superconductivity in an iron chalcogenide superconductor via terahertz optical conductivity and terahertz third-harmonic generation by the injection of photo-carriers. [ABSTRACT FROM AUTHOR]