Correlation effects in ruthenates: LDA+DMFT study
March, 14th 2012 - 11:00 am
Seminar by Dr. Evgeny Gorelov
Forschungszentrum Juelich and Institute of Advanced Simulation of Juelich (Germany)
Title: Correlation effects in ruthenates: LDA+DMFT study
Location: Room 15, - 4th floor, buiding 9, Dipartimento di Fisica - Università di Salerno
Abstract
The ruthenates of the Ruddlesden-Popper family An+1Run O3n+1 where A=(Sr, Ca) are unique among transition-metal oxides, because the change of cation A and/or in the number n of RuO2 layers leads to a variety of collective phenomena, ranging from multi-band Mott transitions to ferro and meta-magnetism. To understand these systems, it is necessary to disentangle the effects of Coulomb repulsion in the 4d4 Ru shell from those of lattice distortions and chemistry. By using the LDA+DMFT (local-density approximation + dynamical mean-field theory) approach, we show how such disentanglement leads to explain the nature of the metal-insulator transition in single-layered Ca ruthenates and the evolution of electronic structure in n-layered Sr ruthenates. We propose LDA+DMFT scheme based on the N-th Order Muffin-Tin Orbital approach and the weak-coupling CT-quantum Monte Carlo method as impurity solver. This method allows us to take into account the full rotationally-invariant Coulomb interaction, as well as full on-site self-energy matrix in orbital space with spin-orbit coupling.