Dynamical Mean-Field Theory for Molecules and Nanostructures

Abstract

Dynamical Mean-Field Theory (DMFT) has established itself as a reliable and well-controlled approximation to study correlation effects in bulk solids and also two-dimensional systems. In combination with standard density-functional theory (DFT) it has been successfully applied to study materials in which localized electronic states play an important role. There are several evidences that for extended systems this DMFT+DFT approach is more accurate than the traditional DFT+U approximation, particularly because of its ability to take into account dynamical effects, such as the time-resolved double occupancy of the electronic orbitals. It was recently shown that this approach can also be successfully applied to study correlation effects in nanostructures. Here, we present a brief review of the recently proposed generalizations of the DFT+DMFT method. In particular, we discuss in details our recently proposed DFT+DMFT approach to study the magnetic properties of nanosystems [V. Turkowski, A. Kabir, N. Nayyar and T. S Rahman, J. Phys.: Condens. Matter (Fast Track) 22, 462202 (2010)] and present its application to small (up to five atoms) Fe and FePt clusters. We demonstrate that being a mean-field approach, DMFT produces meaningful results even for such small systems. We compare our results with those obtained using DFT+U and find that, as in the case of bulk systems, the latter approach tends to overestimate correlation effects in nanostructures. Finally, we discuss possible ways to farther improve the nano-DFT+DMFT approximation and to extend its application to molecules and nanoparticles on substrates and to nonequilibrium phenomena.

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Cited by in corpus (13)

• Quantum embedding theories
• Dynamical vertex approximation in its parquet implementation: application to Hubbard nano-rings
• Green's function methods for single molecule junctions
• Realistic theory of electronic correlations in nanoscopic systems
• On the effect of charge self-consistency in DFT+DMFT calculations for complex transition metal oxides
• Incremental Embedding: A Density Matrix Embedding Scheme for Molecules
• Magnetic anisotropy of FePt nanoparticles
• Validity of the local self-energy approximation: Application to coupled quantum impurities
• Nonadiabatic Time-Dependent Spin-Density Functional Theory for strongly correlated systems
• Dynamical Mean Field Theory for Diatomic Molecules and the Exact Double Counting
• Influence of static disorder and polaronic band formation on interfacial electron transfer in organic photovoltaic devices
• Functional renormalization group study of parallel double quantum dots: Effects of asymmetric dot-lead couplings
• Interaction induced local moments in parallel quantum dots within the functional renormalization group approach