  Using the Boltzmann transport equation, we study phonon residual resistance
of perfect metallic crystals of a finite thickness $d$ along which a weak
constant electric field $E$ is applied. This resistance which is $\propto
d^{-5}E^{-3}$, is due to scattering of electric field-heated electrons with
emission of long-wave acoustic phonons. This electron-phonon interaction is
caused by zero-point vibrations of the atoms in the perfect crystal lattice
sites. Consideration is carried out for Cu, Ag and Au single crystals with the
thickness of about 1 cm, in the fields of the order of 1 mV/cm. Following the
Matthiessen rule, the resistance of the pure crystals the thicknesses of which
are much larger than the electron mean free path, is represented as the sum of
the impurity and phonon residual resistances. The condition on the thickness
$d$ and the field $E$ is found at which the phonon scattering of the
field-heated electrons dominates. Under this condition, the low-temperature
resistances of pure crystals do not depend on the their purity and determine
the phonon residual resistivity of the ideal crystals. The calculations are
performed for Cu with a purity of at least 99.9999%.
