Polarization catastrophe in the polaronic Wigner crystal
Laboratoire d'Études des Propriétés Électroniques des
Solides, CNRS, BP 166, 38042 Grenoble Cedex 9, France
Corresponding author: a firstname.lastname@example.org
Published online: 17 September 2002
We consider a three dimensional Wigner crystal of electrons lying in a host ionic dielectric. Owing to their interaction with the lattice polarization, each localized electron forms a polaron. We study the collective excitations of such a polaronic Wigner crystal at zero temperature, taking into account the quantum fluctuations of the polarization within the Feynman harmonic approximation. We show that, contrary to the ordinary electron crystal, the system undergoes a polarization catastrophe when the density is increased. An optical signature of this instability is derived, whose trend agrees with the experiments carried out in Nd-based cuprates.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 71.38.-k – Polarons and electron-phonon interactions / 71.45.-d – Collective effects
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002