Eur. Phys. J. B 5, 413-417 (1998)
https://doi.org/10.1007/s100510050461

Orbital degrees of freedom and electron correlation in optical absorption of metallic La_1-xSr_xMnO₃ ^*

Department of Physics, Tokyo Institute of Technology, Oh-okayama, Tokyo 152, Japan

Corresponding author: ^a shiba@stat.phys.titech.ac.jp

Received: 13 February 1998
Accepted: 17 March 1998
Published online: 15 October 1998

Abstract

The optical absorption in ferromagnetic metal La_1-xSr_xMnO₃ is anomalous; it has a wide-range absorption up to about 1 eV even at zero temperature. Since 3d electrons in La_1-xSr_xMnO₃ partially fill doubly degenerate e_g orbitals, the orbital degrees of freedom are crucial to understand this metallic system. We argue that the interband transition within e_g orbitals is important in the optical absorption. The optical spectrum is modified also by the inter-orbital Coulomb interaction. We have examined perturbatively the effect of the Coulomb interaction on the spectrum. Available experiments are discussed by comparing with the present results.