A strategy to enhance the light-induced superconductivity of K₃C₆₀

Superconductivity is the ability of certain materials to conduct a direct current (DC) with virtually no resistance. This property is highly sought after and favorable for various technological applications as it increases the efficiency of various electronic and power devices.

In recent years, condensed matter physicists and materials scientists have been trying to identify strategies to improve the superconductivity of specific materials. This includes the substance K₃C₆₀An organic superconductor enters a phase characterized by zero resistance when applying mid-infrared optical pulses.

Researchers at the Max Planck Institute for the Structure and Dynamics of Matter, Università degli Studi di Parma and the University of Oxford have now identified a strategy to enhance the light-induced superconductivity of K.₃C₆₀. This strategy is outlined Natural PhysicsIt has yielded very promising results so far.

„For roughly a decade, we have been exploring the possibility of using light to enhance superconductivity, which creates an equilibrium state at fundamental temperatures above Tc,” Andrea Cavalleri, one of the researchers who conducted the study, told Phys.org. „We’ve shown that it works In some cupratesIn Specific charge exchange salts And K₃C₆₀.”

„In this paper, we investigated the mechanism underlying K₃C₆₀ Optically induced superconductivity using a special optical source reaches a frequency of 10 THz, higher than previously used.”

Cavalleri and his research team are investigating the superconductivity of K₃C₆₀ For a few years now. In their previous experiments, they were able to realize the superconducting phase of this material with excitation photon energies ranging from 80 to 165 MeV (20-40THz).

In their new study, they began to probe the excitation in the material at low energies between 24 and 80 meV (6–20 THz), using a technique previously inaccessible to them. The researchers achieved this using a terahertz source, which creates short-wavelength pulses by combining near-infrared signal beams of two distinct phase-locked optical parametric amplitudes.

„The underlying physics is still unclear, but the experiment targets select molecular vibrations that are directly driven to large amplifications of their resonance frequency,” Cavalleri said. „Driven vibrations appear to couple with electronic states and enhance coupling and coherence leading to superconductivity. The current paper shows that this effect works best at 10 THz, where a specific molecular resonance is observed.”

Recent work by Cavalleri and his collaborators sheds some new light on the possible mechanisms of photo-induced superconductivity in K.₃C₆₀ and potentially other superconductors. Additionally, it introduces a strategy to enable photo-induced superconductivity to last for long periods of time, which could have interesting implications for the development of light-driven quantum technologies.

„We realized a long-lived superconducting state of 10 ns at room temperature,” Cavalleri added. „In principle, this could be used for future quantum devices powered by light. We want to study the properties of this transient state, especially the magnetic properties, and try to compare the properties of the photo-induced phase with the equilibrium. Sc.”