Proximity to Understanding the Cuprates

Modern materials engineering is increasingly dominated by the nanoscale, where surface area trumps volume, so it stands to reason that interfaces between materials are at the forefront for the discovery of new properties. The last few years have seen the discovery of new interface states such as a metal [1] or superconductor [2] between two insulators, magnetism between two nonmagnetic materials [3], and a topologically protected spin current between a semiconductor and vacuum [4]. One type of interface that has been studied for 50 years is still yielding new surprises: the superconductor-metal interface. Writing in Physical Review Letters[5], Colin Parker, Aakash Pushp, Abhay Pasupathy, Kenjiro Gomes, Jinsheng Wen, Zhijun Xu, Shimpei Ono, Genda Gu, and Ali Yazdani, in a collaboration between Princeton University and Brookhaven National Laboratory, both in the US, and the Central Research Institute of Electric Power Industry in Japan, use scanning tunneling microscopy to shed new light on this familiar old interface, resolving it for the first time with nanoscale precision in a cuprate high-Tc superconductor. This precise mapping may bring new insight to a most contentious debate in cuprate superconductivity.