Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: CE: Low-dimensional Systems - Models 1
TT 30.9: Talk
Thursday, March 25, 2010, 11:45–12:00, H20
Spin-liquid and magnetic phases in the anisotropic triangular lattice: the case of κ-(ET)2X — •Luca F. Tocchio1, Alberto Parola2, Claudius Gros1, and Federico Becca3 — 1Institute for Theoretical Physics, Goethe-University Frankfurt, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main, Germany — 2Dipartimento di Fisica e Matematica, Università dell’Insubria, Via Valleggio 11, I-22100 Como, Italy — 3CNR-INFM-Democritos National Simulation Centre and International School for Advanced Studies (SISSA), Via Beirut 2, I-34151 Trieste, Italy
The two-dimensional Hubbard model on the anisotropic triangular lattice, with two different hopping amplitudes t and t′, is relevant to describe the low-energy physics of κ-(ET)2X, a family of organic salts. The ground-state properties of this model are studied by using Monte Carlo techniques, on the basis of a recent definition of backflow correlations for strongly-correlated lattice systems.
The results show that there is no magnetic order for reasonably large values of the electron-electron interaction U and frustrating ratio t′/t = 0.85, suitable to describe the non-magnetic compound with X=Cu2(CN)3. On the contrary, Néel order takes place for weaker frustrations, i.e., t′/t ∼ 0.4 − 0.6, suitable for materials with X=Cu2(SCN)2, Cu[N(CN)2]Cl, or Cu[N(CN)2]Br.