Speaker: Steve Dodge (Simon Fraser University)

Time: August 12, 2024 16:00

Place: 理科楼C302

报告摘要：Over a decade of research has suggested that some metallic compounds can be transformed into superconductors by illuminating them with intense beams of laser light. Recently, we have shown that the experimental evidence for this effect could literally be an optical illusion produced by the high-intensity laser illumination. By examining several influential results on photoinduced superconductivity in K3C60, we have identified a fundamental flaw in their analysis that exaggerates the apparent photoinduced changes to the conductivity. When we account for this error, we find evidence that photoexcitation produces a moderate enhancement of the conductivity, but that there is no need to appeal to a photoinduced phase transition to a superconducting state. Subsequent work on K3C60 has provided quantitative support for our analysis. After discussing our reanalysis of experiments on K3C60, I will describe how this error also distorts the evidence for photoinduced superconductivity in the normal state of cuprate superconductors and in the charge-transfer salt BEDT-TTF. Finally, I will discuss how our reinterpretation raises new and interesting questions about the interaction of light with matter.

[1] J. Steven Dodge, Leya Lopez, and Derek G. Sahota, Phys. Rev. Lett. 130, 146002 (2023).

报告人简介：Steve Dodge joined the Physics Department at Simon Fraser University, British Columbia, in 2000, where he leads an experimental effort to use femtosecond pulses of light to examine the emergent quantum properties of materials. After completing his PhD in 1997, in which he developed Sagnac interferometry for magneto-optical measurements with Aharon Kapitulnik at Stanford University, he pursued his current interest in time-resolved optical methods through postdoctoral work at Lawrence Berkeley National Laboratory, where he worked with Daniel Chemla and Joe Orenstein.