Inducing Superconductivity by a Picosecond Pressure Transient in the Quasi-Two-Dimensional Organic Salt

• Applicant: Professorin Dr. Julia Stähler
• Subject Area: Experimental Condensed Matter Physics
• Term: Funded in 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 70489543

Since the discovery of superconductivity almost 100 years ago, countless studies focused on the origin and driving mechanisms of this phenomenon. In particular the development of high-temperature (high-Tc) superconductors has reached much attention in the past, as the finding of a room-temperature superconductor would, for example, revolutionize electronic engineering. However, despite these efforts, the fundamental processes of unconventional superconductivity are still not understood.Prototype materials for high-Tc superconductivity are the quasi-two-dimensional organic compounds of the BEDT-TTF family. In particular, the κ-(BEDT-TTF)2Cu[N(CN)2]Cl exhibits a very rich phase diagram including a pressure-driven antiferromagnetic insulating-to-superconducting (AF-SC) phase transition below 13 K. So far, all studies of organic superconductors focused on the equilibrium properties of these materials, i.e. the system's response to slow adiabatic changes of the environment. In contrast, the proposed work aims at the investigation of the dynamic formation of the superconducting phase after excitation of a picosecond pressure transient (sound wave) using femtosecond laser pulses. Irradiation of a buffer layer deposited on top of the organic compound launches an acoustic pulse in the material. This pressure transient traverses through the sample at the speed of sound and is expected to induce the AF-SC phase transition. Using this approach, the generation of the superconducting phase could be observed directly in the time domain, and, furthermore, the direction-selective experiment may yield insight into the role of antiferromagnetic fluctuations for superconductivity.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Dr. Andrea Cavalleri