Electron-Phonon Interaction in the Presence of Strong Coulomb Repulsion
- Haldia Government College, Department of Physics (India)
- University of Kalyani, Department of Physics (India)
We consider the Hubbard-Holstein model on a 2D tilted eight-site square lattice at quarter fillings having on-site (λ{sub 1}) and inter-site (λ{sub 2}) electron-phonon (EP) interactions and inter-site Coulomb repulsion (V ). Mobility of electrons decreases, and hence, localization of electrons is favored by λ{sub 1} as well as inter-site Coulomb repulsion in the non-interacting limit (U/t = 0.0). In the interacting case (U/t = 8.0), an initial delocalization effect observed due to the competition between on-site Coulomb repulsion and EP interaction λ{sub 1} though V favors localization. For smaller λ{sub 1}, the competition between λ{sub 2} and V increases the delocalization effect. As λ{sub 2} increases further, localization occurs. In the interacting case, localization occurs at much higher values of λ{sub 2} due to the additional delocalization effect of U. On-site (S0) and/or large bipolarons are formed with λ{sub 1} in the presence of V, and inter-site Coulomb repulsion effectively increases λ{sub 1}. Thus, V favors the formation of S0 bipolarons. However, the formation of S1 bipolarons is suppressed by inter-site Coulomb repulsion. An existence of critical λ{sub 2} = λ{sub 2c} is observed for the formation of on-site (S0) and neighboring-site (S1) bipolarons.
- OSTI ID:
- 22774151
- Journal Information:
- Journal of Superconductivity and Novel Magnetism, Journal Name: Journal of Superconductivity and Novel Magnetism Journal Issue: 1 Vol. 31; ISSN 1557-1939
- Country of Publication:
- United States
- Language:
- English
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