  The cuprate high-temperature superconductors are among the most intensively
studied materials, yet essential questions regarding their principal phases and
the transitions between them remain unanswered. Generally thought of as doped
charge-transfer insulators, these complex lamellar oxides exhibit pseudogap,
strange-metal, superconducting and Fermi-liquid behaviour with increasing
hole-dopant concentration. Here we propose a simple inhomogeneous Mott-like
(de)localization model wherein exactly one hole per copper-oxygen unit is
gradually delocalized with increasing doping and temperature. The model is
percolative in nature, with parameters that are experimentally constrained. It
comprehensively captures pivotal unconventional experimental results, including
the temperature and doping dependence of the pseudogap phenomenon, the
strange-metal linear temperature dependence of the planar resistivity, and the
doping dependence of the superfluid density. The success and simplicity of our
model greatly demystify the cuprate phase diagram and point to a local
superconducting pairing mechanism involving the (de)localized hole.
