Publication Date:
2016-02-23
Description:
Author(s): Roman Kováčik, Sowmya Sathyanarayana Murthy, Carmen E. Quiroga, Claude Ederer, and Cesare Franchini Understanding the electronic and magnetic properties of 3 d transition-metal perovskites is one of the central issues in solid state theory. The physics at play here, involving electron localization and spin/orbital-ordering, is not easily captured by standard theories. By applying a combination of a variety of first-principles methods (DFT, HSE, GW), effective electronic Hamiltonian and Heisenberg spin Hamiltonian the authors study the manganite family R MnO 3 ( R =La, Pr, Nd, Sm, Eu, and Gd) characterized by a progressive enhancement of the orthorhombic distortion which causes an A -type to E -type magnetic transition. This study provides a comprehensive and accurate account of the dependence of the electronic structure and Néel temperature on the structural distortions. In particular, it is shown that the Coulomb repulsion and the Jahn-Teller coupling strength remain unchanged along the series, and are not responsible for the observed transition. Rather, the orthorhombic distortions induces a progressive reduction of the nearest-neighbor hopping term (kinetic) and a concomitant attenuation of the FM in-plane exchange interaction: this induces a a gradual destabilization of the A -type AFM ordering. Monte Carlo simulations predict Néel temperatures in very good agreement with experiment. [Phys. Rev. B 93, 075139] Published Fri Feb 19, 2016
Keywords:
Electronic structure and strongly correlated systems
Print ISSN:
1098-0121
Electronic ISSN:
1095-3795
Topics:
Physics
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