Spin-orbit interaction enhanced polaron effect in two-dimensional semiconductors

It is shown that in two-dimensional semiconductors, the electron-phonon interaction and polaron mass correction are both significantly enhanced by the Rashba spin-orbit coupling. The mass correction is positive for the upper Rashba branch and negative for the lower Rashba branch. Both Rashba branches have the same polaron binding energy, which is higher than that for systems in the absence of spin-orbit interaction. To the leading order, the correction to the binding energy is proportional to the square of the spin-orbit coupling strength.