Title: Re-entrant charge order in overdoped (Bi,Pb)$_{2.12}$Sr$_{1.88}$CuO$_{6+δ}$ outside the pseudogap regime,
Abstract: Charge modulations are considered as a leading competitor of high-temperature
superconductivity in the underdoped cuprates, and their relationship to Fermi
surface reconstructions and to the pseudogap state is an important subject of
current research. Overdoped cuprates, on the other hand, are widely regarded as
conventional Fermi liquids without collective electronic order. For the
overdoped (Bi,Pb)2.12Sr1.88CuO6+{\delta} (Bi2201) high-temperature
superconductor, here we report resonant x-ray scattering measurements revealing
incommensurate charge order reflections, with correlation lengths of 40-60
lattice units, that persist up to at least 250K. Charge order is markedly more
robust in the overdoped than underdoped regime but the incommensurate wave
vectors follow a common trend; moreover it coexists with a single,
unreconstructed Fermi surface, without pseudogap or nesting features, as
determined from angle-resolved photoemission spectroscopy. This re-entrant
charge order is reproduced by model calculations that consider a strong van
Hove singularity within a Fermi liquid framework.