Atomic-layer engineering of cuprate superconductors

Abstract

A technique for atomic layer-by-layer synthesis of cuprate superconductors and other complex oxides has been developed. Thin films with excellent transport properties and atomically flat surfaces and interfaces are obtained. The samples are engineered by stacking molecular layers of different compounds to assemble multilayers and superlattices, by adding or omitting atomic monolayers to create novel compounds, and by doping within specified atomic monolayers to fabricate, for the first time, intra-cell barriers. Apart from manufacturing trilayer Josephson junctions withI cRn>5 mV, this technique enables one to customize both the materials and the devices according to the needs of a specific experiment. A number of fundamental issues, such as the dimensionality of the HTSC state, existence of long-range proximity effects, occurrence of resonant tunneling with a specified number of hops, etc., have been addressed in this way. Synthesis of the first “artificial” metastable HTSC compounds is also reported.