  Breaking down the traditional perception on phonons which are achiral, the
recent discovery of chiral phonon carrying angular momentum provides possible
ways to couple electron, photon, spin, magnon and exciton, etc. We
theoretically proposed an electron-chiral phonon interaction with two-phonon
process, in contrast to conventional electron-phonon interaction, and a kind of
effective Hubbard U through exchanging two chiral phonons is proposed. Taking
two-dimensional diatomic honeycomb lattice as an example, we found this
repulsive Hubbard U mediated by chiral phonons induces unconventional and
high-temperature superconductivity. Moreover, the numerical calculations show
an inverse isotope effect which is consistent with experimental observations in
high-$T_c$ superconductors. Our finding on electron-chiral phonon and the
associated Cooper pair provides a path to understand the high-$T_c$
superconductivity.
