Cuprates: Fermiology, pseudogap, and charge order

Cuprate superconductors remain a central arena for understanding how strong correlations reshape electronic structure and give rise to high-temperature superconductivity. Their phase diagram hosts some of the most important and long-standing problems in condensed matter physics, including the evolution from a correlated insulator to a superconducting state, the origin of the pseudogap, and the emergence of intertwined ordered phases. Because these phenomena are encoded directly in momentum space, cuprates have also provided an ideal setting in which to develop and apply advanced spectroscopic probes of quantum matter.

Our work has contributed to several key advances in this field. Early ARPES studies helped establish the Fermi surface and quasiparticle excitations of overdoped cuprates, while later work clarified how nodal quasiparticle coherence is progressively lost across the phase diagram on approaching the underdoped regime. Using resonant x-ray scattering, we then helped reveal charge order as a universal property of both hole- and electron-doped cuprates, and established its unidirectional character and intimate connection to the pseudogap.

More recently, time-resolved studies have shown how superconductivity can collapse through ultrafast loss of phase coherence, how enhanced phase coherence and pairing can emerge in multilayer cuprates with inequivalent doping across different CuO2​ planes, and in electron-doped cuprates how the pseudogap can arise from short-range spin correlations.