  The self-consistent proton-neutron quasiparticle random phase approximation
approach is employed to calculate $\beta$-decay half-lives of neutron-rich
even-even nuclei with $8\leqslant Z \leqslant 30$. A newly proposed nonlinear
point-coupling effective interaction PC-PK1 is used in the calculations. It is
found that the isoscalar proton-neutron pairing interaction can significantly
reduce $\beta$-decay half-lives. With an isospin-dependent isoscalar
proton-neutron pairing strength, our results well reproduce the experimental
$\beta$-decay half-lives, although the pairing strength is not adjusted using
the half-lives calculated in this study.
