Pressure has long been recognized as a fundamental thermodynamic variable but its
application was previously limited by the available pressure vessels and probes. The …

Superconductivity develops in metals upon the formation of a coherent macroscopic
quantum state of electron pairs. Iron pnictides and chalcogenides are materials that have …

The superconductor iron selenide (FeSe) is of intense interest owing to its unusual
nonmagnetic nematic state and potential for high-temperature superconductivity. But its …

Emergent electronic phenomena in iron-based superconductors have been at the forefront
of condensed matter physics for more than a decade. Much has been learned about the …

The spontaneous reduction of rotational symmetry in a crystalline solid driven by an
electronic mechanism is referred to as electronic nematicity. This phenomenon—initially …

'Conventional'superconductivity, as used in this review, refers to electron–phonon-coupled
superconducting electron pairs described by BCS theory. Unconventional superconductivity …

The interactions that lead to the emergence of superconductivity in iron-based materials
remain a subject of debate. It has been suggested that electron-electron correlations …

Many common crystal structures can be described by a single (or very few) repeated
structural motif (“monomorphous structures”) such as octahedron in cubic halide perovskites …

The coexistence and competition between superconductivity and electronic orders, such as
spin or charge density waves, have been a central issue in high transition-temperature (T c) …

High-temperature superconductivity and a wide variety of exotic superconducting states
discovered in FeSe-based materials have been at the frontier of research on condensed …