https://doi.org/10.1140/epjb/e2004-00219-5
Effect of orbital currents on the restricted optical conductivity sum rule
1
Départment de Physique,
Université de Fribourg, Pérolles, CH-1700 Fribourg, Switzerland
2
Institut de Physique,
Université de Neuchâtel, CH-2000 Neuchâtel, Switzerland
Corresponding author: a lara.benfatto@unifr.ch
Received:
30
April
2004
Published online:
23
July
2004
We derive the restricted optical-conductivity sum rule for a model with circulating orbital currents. It is shown that an unusual coupling of the vector potential to the interaction term of the model Hamiltonian results in a non-standard form of the sum rule. As a consequence, the temperature dependence of the restricted spectral weight could be compatible with existing experimental data for high-Tc cuprates above the critical temperature Tc. We extend our results to the superconducting state, and comment on the differences and analogies between these two symmetry-breaking phenomena.
PACS: 71.10.-w – Theories and models of many-electron systems / 74.25.Gz – Optical properties / 72.15.-v – Electronic conduction in metals and alloys / 74.72.-h – Cuprate superconductors (high-Tc and insulating parent compounds)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004
