Doctoral seminar

Massively Parallel Simulation of Strongly Correlated Materials:
Strongly correlated materials show unusual behavior that offer rich opportunities for applications. Striking examples are high-temperature superconductivity, colossal magneto-resistance, orbital-physics, or spin-charge separation. In these materials the electrons can no longer be considered separately. This is why understanding the physics of strongly correlated materials is one of the grand-challenges in condensed-matter physics. Simple approximations such as the local density approximation fail, due to the importance of the Coulomb repulsion between localized electrons. Instead we have to resort to non-perturbative many-body techniques. Such calculations are, however, only feasible for quite small model systems. This means that the full Hamiltonian of a real material has to be replaced by a lattice model comprising only the most important electronic degrees of freedom, while the effect of all other electrons is included in an average way. Realistic calculations of strongly correlated materials need to include a sufficient number of these electronic degrees of freedom.
With the recent availability of massively parallel supercomputers, such realistic calculations of strongly correlated materials are becoming a reality. The efficient use of highly parallel systems requires, however, new algorithmic approaches. We discuss our novel implementations of the Lanczos method and quantum Monte Carlo for cluster and dynamical mean-field calculations and present recent results on the spin-charge separation in organic charge-transfer salts and on orbital-order in transition-metal compounds.

Speaker: Prof. Dr. Erik Koch, Computational Materials Science, German Research School for Simulation Sciences

Date: Monday, July 19, 2010

Time: 16:15

Location: Lecture Room 001, German Research School for Simulation Sciences, Schinkelstr. 2a, 52062 Aachen