For 10 points, name these materials that lose all resistance to current above the 30 Kelvin limit set by BCS theory
These materials are commonly studied using 6 eV laser-based angle-resolved photoemission spectroscopy. Tuning the chemical potential near a 2.5-order quantum phase transition generates shape resonances in these materials, thereby breaking lattice symmetry and creating superstripes. Fermi arcs form pockets centered on the corners of the Brillouin zone in the pseudogap phase that occurs in an underdoped variety of these materials. The resonating valence bond and spin fluctuation theories are competing explanations of these materials' namesake phenomenon. Melt-textured examples of these materials are close to ideally hard because they exhibit strong flux pinning of Abrikosov vortices. Bednorz and Müller won the 1987 Nobel Prize in Physics for discovering these materials, which include iron pnictides and cuprates like YBCO. For 10 points, name these materials that lose all resistance to current above the 30 Kelvin limit set by BCS theory
These materials are commonly studied using 6 eV laser-based angle-resolved photoemission spectroscopy.
high-temperature superconductors [or HTS; accept cuprate superconductors before "iron pnictides"; prompt on "(Type II) superconductors"; do not accept or prompt on "Type I superconductors"]