“…However, this crystal phase presents large spontaneous and piezoelectric polarization fields that limit the free‐carrier recombination efficiency (Wei et al, ). Recently, in order to avoid the intrinsic polarization fields in electronic devices, intensive efforts have been made to grow the group III nitrides in the metastable phase, which has a cubic (zinc blende) structure with space group F‐43m (As et al, ; Casallas‐Moreno et al, ; Wei et al, ). The cubic phase does not exhibits spontaneous polarization due to the high crystal symmetry, and all piezoelectric polarization components vanish along the <100> direction of growth (Sun and Towe, ), contrary to the wurtzite type where the total polarization is never zero for any orientation (Wei et al, ).…”