Organic charge transfer salts: How can we connect the crystal structure to complex manybody effects?
Dr. Harald O. Jeschke
Institut für theoretische Physik, Universität Frankfurt
17:15 - 18:15 Tuesday 16 December 2014 TUG P2 Organic salts based on donor molecules like TMTTF or BEDT-TTF or on acceptor molecules like Pd(dmit)2 form large families of charge transfer materials with fascinating phase diagrams. The molecular orbitals in these materials form narrow bands, leading to strong interactions between the electrons. Thus, many phenomena for which transition metal oxides are famous like magnetism, superconductivity, charge order and Mott physics can be found in organic charge transfer salts as well.
Here, we tackle the problem how to theoretically understand and predict that small changes in pressure, temperature or chemical substitution can lead to very diverse phases as observed experimentally. We study a number of BEDT-TTF based charge transfer salts in the framework of ab initio density functional theory (DFT) and determine the parameters of the effective Hubbard Hamiltonian
describing the low energy excitations [1]. For the spin liquid candidate kappa-(BEDT-TTF)2Cu2(CN)3, we investigate the question if the structures determined at various temperatures lead to different effective Hamiltonian representations [2]. For the Fabre salts (TMTTF)2X, we compare the properties of the underlying Hamiltonian for a series of different anions X [3]. We also use a combination of DFT and dynamical mean field theory to study the electronic and optical
properties of the Mott insulator kappa-(BEDT-TTF)2Cu[N(CN)2]Cl [4].
[1] H.C. Kandpal, I. Opahle, Y.-Z. Zhang, H. O. Jeschke, R. Valenti, Phys. Rev. Lett. 103, 067007 (2009).
[2] H. O. Jeschke, M. de Souza, R. Valenti, R. S. Manna, M. Lang, J. A. Schlueter, Phys. Rev. B 85, 035125 (2012).
[3] A. C. Jacko, H. Feldner, E. Rose, F. Lissner, M. Dressel, R. Valenti, H. O. Jeschke, Phys. Rev. B 87, 155139 (2013).
[4] J. Ferber, K. Foyevtsova, H. O. Jeschke, R. Valenti, Phys. Rev. B 89, 205106 (2014).
|
