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arXiv · 1802.06593

Electron pairing: from metastable electron pair to bipolaron

Guo-Qiang Hai·Ladir Cândido·Braulio G. A. Brito·François M. Peeters
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Abstract

Starting from the shell structure in atoms and the significant correlation within electron pairs, we distinguish the exchange-correlation effects between two electrons of opposite spins occupying the same orbital from the average correlation among many electrons in a crystal. In the periodic potential of the crystal with lattice constant larger than the effective Bohr radius of the valence electrons, these correlated electron pairs can form a metastable energy band above the corresponding single-electron band separated by an energy gap. In order to determine if these metastable electron pairs can be stabilized, we calculate the many-electron exchange-correlation renormalization and the polaron correction to the two-band system with single electrons and electron pairs. We find that the electron-phonon interaction is essential to counterbalance the Coulomb repulsion and to stabilize the electron pairs. The interplay of the electron-electron and electron-phonon interactions, manifested in the exchange-correlation energies, polaron effects, and screening, is responsible for the formation of electron pairs (bipolarons) that are located on the Fermi surface of the single-electron band.

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Guo-Qiang Hai, Ladir Cândido, Braulio G. A. Brito, François M. Peeters. 2018-02-19. Electron pairing: from metastable electron pair to bipolaron. https://doi.org/10.1088/2399-6528%2Faaaee0

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