Eur. Phys. J. B 78, 525-529 (2010)
https://doi.org/10.1140/epjb/e2010-10517-x

Hartree-Fock approximation of bipolaron state in quantum dots and wires

¹ Department of Physics, Izmir Institute of Technology, 35430 Izmir, Turkey
² Department of Physics, Faculty of Sciences, Ankara University, 06100 Tandogan, Ankara, Turkey
³ School of Physics, University of Hyderabad, Hyderabad, 500046, India
⁴ Department of Physics, Bilkent University, 06800 Bilkent, Ankara, Turkey

Corresponding author: ^a tugrulsenger@iyte.edu.tr

Received: 2 July 2010
Revised: 4 November 2010
Published online: 10 December 2010

Abstract

The bipolaronic ground state of two electrons in a spherical quantum dot or a quantum wire with parabolic boundaries is studied in the strong electron-phonon coupling regime. We introduce a variational wave function that can conveniently conform to represent alternative ground state configurations of the two electrons, namely, the bipolaronic bound state, the state of two individual polarons, and two nearby interacting polarons confined by the external potential. In the bipolaron state the electrons are found to be separated by a finite distance about a polaron size. We present the formation and stability criteria of bipolaronic phase in confined media. It is shown that the quantum dot confinement extends the domain of stability of the bipolaronic bound state of two electrons as compared to the bulk geometry, whereas the quantum wire geometry aggravates the formation of stable bipolarons.