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.

Highlights

  • Since the discovery of high Tc superconductivity by Bednorz and Müller [1] in 1986, great progresses have been made in the experimental and theoretical investigation of unconventional superconductivity

  • 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 electronphonon interaction is essential to counterbalance the Coulomb repulsion and to stabilize the electron pairs

Read more

Summary

March 2018

Any further distribution of distinguish the exchange-correlation effects between two electrons of opposite spins occupying the this work must maintain attribution to the same orbital from the average correlation among many electrons in a crystal. In the periodic potential author(s) and the title of of the crystal with lattice constant larger than the effective Bohr radius of the valence electrons, these the work, journal citation and DOI. 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. 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

Introduction
Metastable electron pairs in crystal
Metastable electron-pair band in 2D square lattices
Hamiltonian of the two-band many-electron system interacting with LO-phonons
Electron-electron interactions with single electrons and electron pairs
Findings
Summary and outlook
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call