报告题目：A nano-scale approach to point-contact Andreev reflection spectroscopy

报 告 人：Haibing Peng，Department of Physics and the Texas Center for Superconductivity, University of Houston

报告时间：7月9日（周一）16:00

报告地点：理科楼三楼报告厅

报告摘要：Point-contact spectroscopy has been an important tool not only for probing elementary excitations (e.g. phonons and magnons) in solids, but also for querying the energy gap structures in superconductors via Andreev reflection (AR) at the interface of normal metal/superconductor (N-S) contacts. However, significant barriers remain to improve thermo-mechanical stability and provide diagnostic information on point contacts traditionally fabricated by mechanically pressing a metal tip against a bulk superconductor. In this talk, I will discuss efforts of my group in establishing a distinct experimental approach to implementing point-contact AR spectroscopy with diagnostic capability via a unique design of nano-scale N-S devices with excellent thermo-mechanical stability, and have employed this method to unveil the existence of two energy gaps in Fe1+yTe1-xSex which is important for understanding the pairing mechanism in recently discovered Fe-based superconductors. This work opens a pathway to the study of emerging functional materials such as 2D layered materials via the integration of nano-fabrication technology