X-ray techniques have been used for more than a century to study the atomic and electronic
structure in practically any type of material. The advent of correlated electron systems, in …

Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of
orders of magnitude, and are widely observed in condensed-matter systems. This article …

The competition between antiferromagnetism and hole motion in two-dimensional Mott
insulators lies at the heart of a doping-dependent transition from an anomalous metal to a …

This article reviews the physics of high-temperature superconductors from the point of view
of the doping of a Mott insulator. The basic electronic structure of cuprates is reviewed …

Theoretical ideas and experimental results concerning high-temperature superconductors
are reviewed. Special emphasis is given to calculations performed with the help of …

ONE of the long-standing mysteries associated with the high-temperature copper oxide
superconductors concerns the anomalous suppression1 of superconductivity in La2 …

We present an experimental review of the nature of the pseudogap in the cuprate
superconductors. Evidence from various experimental techniques points to a common …

Although the vast majority of high-T c cuprate superconductors are hole-doped, a small
family of electron-doped compounds exists. Underinvestigated until recently, there has been …

A concept—quantum order—is introduced to describe a new kind of orders that generally
appear in quantum states at zero temperature. Quantum orders that characterize the …

The character of the ground state of an antiferromagnetic insulator is fundamentally altered
following addition of even a small amount of charge. The added charge is concentrated into …