Phys.org October 12, 2023
Photoexcitation at terahertz and mid-infrared frequencies has emerged as an effective way to manipulate functionalities in quantum materials, in some cases creating non-equilibrium phases that have no equilibrium analogue. In K3C60, a metastable zero-resistance phase was observed that has optical properties, nonlinear electrical transport, and pressure dependencies compatible with non-equilibrium high-temperature superconductivity. An international team of researchers (Germany, Switzerland, Italy, UK) demonstrated a two-orders-of-magnitude increase in photo-susceptibility near 10 THz excitation frequency. At these drive frequencies, a metastable superconducting-like phase was observed up to room temperature. The discovery of a dominant frequency scale sheds light on the microscopic mechanism underlying photo-induced superconductivity. It also indicates a path towards steady-state operation, limited at present by the availability of a suitable high-repetition-rate optical source at these frequencies… read more. Open Access TECHNICAL ARTICLE
Crystal structure and phase diagram of K3C60. Credit: Nature Physics, 05 October 2023