Jahn-Teller Coupled Charge Density Wave in A Two Orbital Double Exchange System
نویسندگان
چکیده
In a two orbital double exchange model we formulate Jahn-Teller coupled charge density wave in half-filled limit. Softening of Jahn-Teller phonons corresponding to distortion modes Q2 or Q3 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 Q2 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 Q2. ∗ e-mail: [email protected]
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