J.E. Hoffman, Harvard

Title: High Tc Superconductivity in a Single Atomic Layer of FeSe  (Video)

Abstract: Superconductivity - the lossless transmission of electrical current without any resistivity - could revolutionize energy, transportation, communication, and healthcare industries - if only materials could be found to superconduct at room temperature. But the remarkable recent discovery of superconductivity above 100 Kelvin in a single atomic layer of FeSe (compared to the impractically low Tc=8K in bulk FeSe) has prompted tremendous excitement and numerous pressing questions. What is the mechanism of the order-of-magnitude Tc enhancement in FeSe? Could FeSe be a topological superconductor? What applications might one envision with such a 2D superconductor? Are there other high-Tc interface superconductors just waiting to be discovered? I will review current experimental progress towards addressing these questions, then discuss our own growth (via molecular beam epitaxy) and atomic resolution imaging (via scanning tunneling microscopy) of single layer FeSe. We use quasiparticle interference to access the band structure of filled and empty states, and to explore the pairing symmetry.