Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 27: Solids at Low Temperature - New Materials

TT 27.1: Vortrag

Dienstag, 8. März 2005, 12:00–12:15, TU H3027

Wigner crystallization in Na₃Cu₂O₄ and Na₈Cu₅O₁₀ chain compounds — •P. Horsch, M. Sofin, M. Mayr, and M. Jansen — Max-Planck-Institut fuer Festkoerperforschung, D-70569 Stuttgart, Germany

We report the synthesis of novel edge-sharing chain systems Na₃Cu₂O₄ and Na₈Cu₅O₁₀, which form insulating states with commensurate charge order. We identify these systems as one-dimensional Wigner lattices, where the charge order is determined by long-range Coulomb interaction and the number of holes in the d-shell of Cu. Our interpretation is supported by X-ray structure data as well as by an analysis of magnetic susceptibility and specific heat data. Remarkably, due to large second neighbor Cu-Cu hopping, these systems allow for a distinction between the (classical) Wigner lattice and the 4 k_F charge-density wave of quantum mechanical origin.