Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 68: Correlated Electrons: (General) Theory 1

TT 68.7: Topical Talk

Mittwoch, 18. März 2015, 16:45–17:15, H 3010

Structural Stability and Lattice Dynamics of Correlated Electron Materials — •Ivan Leonov — TP III, Center for Electronic Correlations and Magnetism, University of Augsburg, Germany

I will discuss a computational scheme for the investigation of complex correlated electron materials which is able to treat atomic displacements, and hence structural transformations, caused by electronic correlations. It combines ab initio band structure and dynamical mean-field theory and is implemented in terms of plane-wave pseudopotentials. This approach is employed to compute the electronic structure and phase stability of several correlated electron materials. In particular, we study the cooperative Jahn-Teller effect in paramagnetic KCuF₃, the electronic properties and lattice dynamics of Fe at the bcc-fcc phase transition as a function of temperature, the electronic state and structural stability of V₂O₃ at the Mott-Hubbard metal-insulator transition, and the electronic structure and phase stability of FeSe. Our results for the equilibrium crystal structure, phase stability, and lattice dynamics are in quantitative agreement with experimental data. We find that electronic correlations are important to explain the lattice stability of correlated materials. We also present our recent results obtained by the LDA+DMFT approach implemented with the linear-response formalism regarding atomic displacements which makes it possible to evaluate the interatomic forces and, thereby, determine the atomic displacements. Our results show an overall good agreement between the total energy and force computations of the equilibrium atomic positions.