Correlation effects and configuration of a one-dimensional bipolaron

• Published in: Physics letters. A 2019-12, Vol.383 (35), p.126003, Article 126003
• Main Authors: Kashirina, N.I., Lakhno, V.D.
• Format: Article
• Language: English
• Subjects: Bipolaron; Electron-phonon interaction; Low-dimensional systems; Polaron
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2019.126003

•Electronic correlations play a decisive role in stabilizing 1D bipolaron.•1D bipolaron can be stable in both one-center and two-center configurations.•Different configurations of 1D bipolaron are separated by a potential barrier.•1D two-center optical bipolaron is more stable compared to one-center one. The aim of the work is to study the structure of a one-dimensional (1D) bipolaron, taking into account three types of correlation effects: such as interelectronic correlations caused by the direct dependence of the wave function on the distance between electrons as well as the one-center and two-center correlations. Gaussian orbitals with exponentially-correlated multipliers were used for variational calculations. It is shown that in the domain of existence of an 1D optical bipolaron – unlike in a 3D system – a two-center bipolaron is formed. The one-center bipolaron configuration becomes energetically favorable as compared to the two-center one for VC≤1.2 (where VC is interelectronic repulsion parameter). This domain corresponds to an acoustical or acousto-optical bipolaron in the strong-coupling limit.