  Coleman-Weinberg (CW) phenomena for the case of gravitons minimally coupled
to massless scalar field is studied. The one loop effect completely vanishes if
there is no self interaction term present in the matter sector. The one loop
effective potential is shown to develop an instability in the form of acquiring
an imaginary part, which can be traced to the tachyonic pole in the graviton
propagator. The finite temperature counterpart of this CW potential is computed
to study the behaviour of the potential in the high and low temperature regimes
with respect to the typical energy scale of the theory. Finite temperature
contribution to the imaginary part of gravitational CW potential exhibits a
damped oscillatory behaviour; all thermal effects are damped out as the
temperature vanishes, consistent with the zero-temperature result. Possibility
of symmetry restoration at high temperature is also depicted.
