Eur. Phys. J. B 3, 149-154 (1998)
https://doi.org/10.1007/s100510050295

Optical conductivity of the Bechgaard salts: the sum rules revisited

¹ Laboratorium für Festkörperphysik, ETH-Zürich, 8093 Zürich, Switzerland
² Laboratoire de Physique Quantique, Université Paul Sabatier, 31062 Toulouse, France

Corresponding author: ^a degiorgi@solid.phys.ethz.ch

Received: 19 December 1997
Revised: 9 March 1998
Accepted: 23 March 1998
Published online: 15 May 1998

Abstract

The validity of the optical sum rules has been addressed eversince and was always matter of debate. Particularly controversial is the proof that the partial sum rules can be extended to both optical conductivity and energy loss function. We show in this paper that for both transverse (optical conductivity) and longitudinal (energy loss function) absorption processes the corresponding sum rule can be theoretically established and through appropriate conditions for the integration limits exactly verified. We also focus our attention on the one-dimensional case within the microscopic Hubbard model. An application of these concepts to the quasi one-dimensional systems, for which we have chosen the organic (TMTSF)₂PF₆ material, will also be presented.