There is now compelling evidence that the normal state of
superconducting overdoped cuprates is a strange metal comprising two
distinct charge sectors, one governed by coherent quasiparticle
excitations, the other seemingly incoherent and characterized by
non-quasiparticle (Planckian) dissipation. The zero-temperature
superfluid density n_s(0)ns(0)
of overdoped cuprates exhibits an anomalous depletion with increased
hole doping pp,
falling to zero at the edge of the superconducting dome. Over the same
doping range, the effective zero-temperature Hall number
n_{\rm H}(0)
transitions from pp
to 1 + pp.
By taking into account the presence of these two charge sectors, we
demonstrate that in the overdoped cuprates
Tl_22Ba_22CuO_{6+\delta}6+δ
and La_{2-x}2−xSr_xxCuO_44,
the growth in n_s(0)ns(0)
as pp
is decreased from the overdoped side may be compensated by the loss of
carriers in the coherent sector. Such a correspondence is contrary to
expectations from conventional BCS theory and implies that
superconductivity in overdoped cuprates emerges uniquely from the sector
that exhibits incoherent transport in the normal state.
Possible superconductivity from incoherent carriers in overdoped cuprates
