  Trilayer graphene in the fractional Quantum Hall Effect regime displays a set
of unique interaction-induced transitions that can be tuned entirely by the
applied bias voltage. These transitions occur near the anti-crossing points of
two Landau levels. In a large magnetic field ($> 8$ T) the electron-electron
interactions close the anti-crossing gap, resulting in some unusual transitions
between different Landau levels. For the filling factor $\nu=\frac23$, these
transitions are accompanied by a change of spin polarization of the ground
state. For a small Zeeman energy, this provides an unique opportunity to
control the spin polarization of the ground state by fine tuning the bias
voltage.
