MATERIALS RESEARCH NETWORK – COLLABORATIVE RESEARCH: DECOHERENCE, CORRELATIONS AND SPIN EFFECTS ON NANOSTRUCTURED MATERIALS NANCY P. SANDLER, OHIO UNIVERSITY, DMR STM measurements of the Kondo temperature inside and throughout a Co porphyrin molecule deposited on Cu(111) can be understood thanks to NRG calculations in terms of the spatially-dependent spin density of states arising from large electron transfer to and strong hybridization inside the molecule. STM map of Co-porphyrin (Hla et al.) Spin density of states throughout the molecule (Marzari et al.) Physical Review Letters 2010 Extended Kondo Correlations Throughout a Magnetic Adsorbed Molecule

Suppression of Kondo Screening by the Dicke Effect Utilizing numerical group renormalization calculations, we have shown that the presence of nearby resonance states (Dicke effect) results in strong suppression and even total cancellation of the Kondo screening. Physical Review B 2010 Materials Research Network – Collaborative Research: Decoherence, Correlations and Spin Effects on Nanostructured Materials Nancy P. Sandler, Ohio University, DMR

New results on Graphene – our research shows that: Energy bands for zigzag nanoribbons: dotted lines obtained with tight binding model, full lines corespond to Majorana fermion Hamiltonian. Zigzag ribbons can be described in terms of Majorana fermions. Zigzag ribbons are special case of square lattices with anomalous width-dependence Charge density difference between two graphene sublattices as a function of ribbon width. As square lattice becomes graphene, wave functions become more localized along the edges. Graphene lattice as square lattice. When the parameter η takes the value 0, the square lattice reduces to a graphene lattice. New Journal of Physics 2009 Materials Research Network – Collaborative Research: Decoherence, Correlations and Spin Effects on Nanostructured Materials Nancy P. Sandler, Ohio University, DMR

Workshop in Rio de Janeiro The MWN-CIAM collaboration met in Rio de Janeiro July 2010 to exchange ideas on current projects, as well as make concrete plans for future projects within the collaboration. The workshop was held at PUC-Rio and attended by over twenty researchers from Brazil, Chile, Spain, Argentina and the US. Discussion/summary sessions were held at the end of each day with active participation of young investigators. Materials Research Network – Collaborative Research: Decoherence, Correlations and Spin Effects on Nanostructured Materials Nancy P. Sandler, Ohio University, DMR