  Superconductivity in cuprate superconductors occurs upon charge-carrier
doping Mott insulators, where a central question is what mechanism causes the
loss of electrical resistance below the superconducting (SC) transition
temperature? In this review, we attempt to summarize the basic idea of the
kinetic-energy driven SC mechanism in the description of superconductivity in
cuprate superconductors. The mechanism of the kinetic-energy driven
superconductivity is purely electronic without phonons, where the
charge-carrier pairing interaction arises directly from the kinetic energy by
the exchange of spin excitations in the higher powers of the doping
concentration. This kinetic-energy driven d-wave SC-state is controlled by both
the SC gap and quasiparticle coherence, which leads to that the maximal SC
transition temperature occurs around the optimal doping, and then decreases in
both the underdoped and overdoped regimes. In particular, the same
charge-carrier interaction mediated by spin excitations that induces the
SC-state in the particle-particle channel also generates the normal-state
pseudogap state in the particle-hole channel. The normal-state pseudogap
crossover temperature is much larger than the SC transition temperature in the
underdoped and optimally doped regimes, and then monotonically decreases upon
the increase of doping, eventually disappearing together with superconductivity
at the end of the SC dome. This kinetic-energy driven SC mechanism also
indicates that the strong electron correlation favors superconductivity, since
the main ingredient is identified into a charge-carrier pairing mechanism not
from the external degree of freedom such as the phonon but rather solely from
the internal spin degree of freedom of the electron. The typical properties of
cuprate superconductors discussed within the framework of the kinetic-energy
driven SC mechanism are also reviewed.
