This article gives an overview of both theoretical and experimental developments
concerning states with lattice symmetry breaking in the cuprate high-temperature …

I review theoretical ideas and implications of experiments for the gap structure and symmetry
of the Fe-based superconductors. Unlike any other class of unconventional …

The recently discovered Fe-pnictide and chalcogenide superconductors display low-
temperature properties suggesting superconducting gap structures which appear to vary …

The superconducting state is characterized by a pairing of electrons with a superconducting
gap on the Fermi surface. In iron-based superconductors, an unconventional pairing state …

We show that interlayer current induces topological superconductivity in twisted bilayers of
nodal superconductors. A bulk gap opens and achieves its maximum near a “magic” twist …

The unclear relationship between cuprate superconductivity and the pseudogap state
remains an impediment to understanding the high transition temperature (T c) …

Phase-sensitive measurements of the superconducting gap in Fe-based superconductors
have proven more difficult than originally anticipated. While quasiparticle interference (QPI) …

A crucial step in revealing the nature of unconventional superconductivity is to investigate
the symmetry of the superconducting order parameter. Scanning tunneling spectroscopy has …

(L i 0.8 F e 0.2) OHFeSe is a newly discovered intercalated iron-selenide superconductor
with a T c above 40 K, which is much higher than the T c of bulk FeSe (8 K). Here we report a …

Motivated by the recent observations of small Fermi energies and comparatively large
superconducting gaps, present also on bands not crossing the Fermi energy (incipient …