An improved variational approach to off-diagonal exciton-phonon coupling

• Main Authors: Zhao, Yang, Li, Guangqi, Sun, Jin, Wang, Weihua
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Physics::Atomic physics::Solid state physics
• Online Access: https://hdl.handle.net/10356/92421; http://hdl.handle.net/10220/6747
• Institution: Nanyang Technological University

A state-of-the-art variational wave function incorporating Jastrow-type exciton-phonon correlations, the global-local Ansatz, is utilized to elucidate exciton-phonon correlations in a generalized form of the Holstein Hamiltonian with the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. Much lowered ground-state energies are found for the global-local Ansatz when compared with the previously studied Toyozawa Ansatz. A three-dimensional phase diagram spanned by the transfer integral and two forms of exciton-phonon coupling is given to illustrate polaronic self-trapping near the zone center.