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 …

A term first coined by Mott back in 1968 a “pseudogap” is the depletion of the electronic
density of states at the Fermi level, and pseudogaps have been observed in many systems …

Recently, the discovery of superconductivity with a critical temperature T c up to 80 K in
Ruddlesden–Popper phases La n+ 1 Ni n O 3 n+ 1 (n= 2) under pressure has garnered …

High-temperature copper oxide superconductors consist of stacked CuO2 planes, with
electronic band structures and magnetic excitations that are primarily two-dimensional,, but …

In cuprate high-temperature superconductors, an antiferromagnetic Mott insulating state can
be destabilized toward unconventional superconductivity by either hole or electron doping …

High T c superconductors show a rich variety of phases associated with their charge
degrees of freedom. Valence charges can give rise to charge ordering or acoustic plasmons …

Over the past few years, Sr2IrO4, a single-layer member of the Ruddlesden–Popper series
iridates, has received much attention as a close analog of cuprate high-temperature …

How coherent quasiparticles emerge by doping quantum antiferromagnets is a key question
in correlated electron systems, whose resolution is needed to elucidate the phase diagram …

The principal purpose of this topical review is to single out some of the universal features of
high-temperature (high-T c) and related strongly-correlated systems, which can be …

Despite significant progress in resonant inelastic x-ray scattering (RIXS) experiments on
cuprates at the Cu L-edge, a theoretical understanding of the cross section remains …