Tayloring the Properties of Layered Oxides : Toward High-T _c Nanoengineering

Abstract

13 years ago, appeared the famous paper¹ by Bednorz and Müller, that announced a striking discovery of high-T_c superconductivity in cuprates. Some 50’000 papers later, we are still trying to understand these versatile solids and control their electronic phase diagram. Nevertheless successful oxide electronic technology is already in its infancy and should have its niche in the 21st century, even if the Si and GaAs technologies remain dominant. In a direct analogy with the succesfull (Al)GaAs band-gap engineering technology I discuss the strategy to achieve similar technology with layered oxides. This is currently hindred by some intrinsic materials problems (various types of disorder) as well as some fundamental restrictions (difficult local doping and nonhomogeneous oxygen distribution). Therefore I present some of the most relevant recent experiments and discuss open questions across a rather complex electronic phase diagram. I argue that we will gradually solve all the obstacles to fully exploit the electronic phase diagram of layered cuprates (and related solids) and eventually taylor their electronic properties and novel applications within an integrated nano-engineering technology of the 21^st century.