Atomic Layer-by-Layer Engineering of High Tc Materials and Heterostructure Devices

Abstract

Oxides exhibit most of the interesting phenomena known to occur in solid-state systems. As a class of materials they may be richer in phenomenology than any other comparable class. Oxides can be insulators, semiconductors, or metals. The copperoxide-based compounds we have studied are superconductors with the highest critical temperatures. In some oxides, electrons manifest simple single-particle transport properties, with a high mobility; in others, they show strongly correlated behavior resulting in a Mott-Hubbard transition, localization, and charge- or spin-density waves. In some oxides, electron-phonon coupling leads to polaronic transport. Others show collective states such as magnetism; in some there are large local magnetic moments that can couple to form ferromagnetic or antiferromagnetic phases that exist up to high temperatures. Yet others have large nonlinear dielectric and optical properties. In fact, it would seem there is very little that some such oxide couldn't do for or to the experimenter.