  We consider cotunneling through a quantum dot in the presence of spin-flip
processes induced by the coupling to acoustic phonons of the surrounding. An
expression for the phonon-assisted cotunneling current is derived by means of a
generalized Schrieffer-Wolff transformation. The influence of the spin-phonon
coupling on the heating of the dot is considered. The result is evaluated for
the case of a parabolic semiconductor quantum dot with Rashba and Dresselhaus
spin-orbit coupling and a method for the determination of the spin-phonon
relaxation rate is proposed.
