  In a two orbital double exchange model we formulate Jahn-Teller coupled
charge density wave in one electron per lattice site limit. Softening of
Jahn-Teller phonons corresponding to distortion modes $Q_2$ or $Q_3$ associated
with perfect nesting of Fermi surface leads to this instability at low
temperature. The gap equation for charge density wave state and its dependences
on electron-lattice coupling are calculated explicitly when any one of the
Jahn-Teller modes is excited cooperatively.
  We find that the $Q_2$ distortion mode yields lowest free energy.
  The calculated heat capacity for each mode shows $T^3$ behavior at low
temperature. Effect of electron-lattice interaction on collective mode, such as
amplitude mode, is more pronounced when the excited mode is $Q_2$.
