Pressure-induced insulator-metal transition in LaMnO(3): a slave-boson approach.
The recent observation of a pressure-induced insulator to metal (I-M) transition in pure LaMnO3 [I. Loa, Phys. Rev. Lett. 87, 125501 (2001).10.1103/PhysRevLett.87.125501], opens the way to a study of the role of the orbital degrees of freedom on the electronic structure in a stoichiometric material and its interaction with lattice distortion. To obtain the energy of the system, we resort to a slave boson description for the electronic part and add an elastic term associated to the Jahn-Teller distortion. We obtain the evolution of the electronic structure and the Jahn-Teller distortion with pressure. We find that the Jahn-Teller distortion does not vanish before entering the metallic phase, that the gap closes with pressure in a way similar to that indicated by the temperature dependence of the conductivity, and that both Coulomb and Jahn-Teller interactions are necessary to describe appropriately the phase transition in LaMnO3.
Instituto Balseiro and Centro Atómico Bariloche, CNEA, 8400 San Carlos de Bariloche, Argentina.
Javier D
JD
Fuhr
Michel
M
Avignon
Blas
B
Alascio