https://doi.org/10.1140/epjb/e2002-00227-5
Polaronic behavior in single- and many-electron Holstein model: A new perturbation approach
Department of Physics, Shanghai Jiao Tong University,
Shanghai 200030, PR China
Corresponding author: a hqs031@mail1.sjtu.edu.cn
Received:
27
December
2001
Revised:
8
April
2002
Published online:
31
July
2002
A new perturbation approach is developed for single- and
many-electron Holstein model in one-, two-, and three-dimension.
The results show that this approach has a good agreement with the Migdal
theory in the adiabatic regime when the coupling is moderate
(
), but with the Lang-Firsov theory in the antiadiabatic regime
(
). In the intermediate region, our approach can
describe the transition from a large-polaron Fermi-liquid
to the small-polaron, and this transition may be discontinuous in
adiabatic regime, which means a phase transition appears in
many-electron system. In single-electron case, we eliminate the
abrupt transition using the degenerate perturbation theory, and the
calculated ground state energy and effective mass are successfully
compared with those of previous authors. Besides, the method has
the advantage of requiring little computational effort.
PACS: 71.38.-k – Polarons and electron-phonon interactions / 64.60.-i – General studies of phase transitions / 71.30.+h – Metal-insulator transitions and other electronic transitions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
