Gain of the kinetic energy of bipolarons in the t-J-Holstein model based on electron-phonon coupling

TL;DR

This paper investigates how increasing electron-phonon coupling in the t-J-Holstein model enhances bipolaron kinetic energy and reduces their effective mass, highlighting the cooperative role of magnetic and lattice interactions in bipolaron formation.

Contribution

It demonstrates that stronger electron-phonon coupling leads to higher bipolaron kinetic energy and smaller effective mass, revealing new insights into bipolaron dynamics within the t-J-Holstein model.

Findings

Bipolaron kinetic energy increases with electron-phonon coupling.

Effective bipolaron mass decreases compared to polaron mass.

Magnetic and lattice interactions cooperatively form spin-lattice bipolarons.

Abstract

With increasing electron-phonon coupling as described within the t-J-Holstein model, bipolaron kinetic energy is lowered in comparison with that of the polaron. This effect is accompanied with "undressing" of bipolaron from lattice degrees of freedom. Consequently, the effective bipolaron mass becomes smaller than the polaron mass. Magnetic as well as lattice degrees of freedom cooperatively contribute to formation of spin-lattice bipolarons.