Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Correlated Electrons: Poster Session
TT 32.73: Poster
Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B
Ground state phases of the spin-1/2 J1–J2 frustrated Heisenberg model on the square lattice: a coupled cluster study — •Rachid Darradi1, Jörg Schulenburg2, Sven Krüger3, Ronald Zinke1, and Johannes Richter1 — 1Institut für Theoretische Physik, Otto-von-Guericke Universität Magdeburg, 39016 Magdeburg, Germany — 2Universitätsrechenzentrum, Universität Magdeburg, P.O. Box 4120, D-39016 Magdeburg, Germany — 3IESK, Kognitive Systeme, Universität Magdeburg, P.O. Box 4120, D-39016 Magdeburg, Germany
We investigate the ground state phases of spin-1/2 frustrated Heisenberg antiferromagnet on the square lattice (J1–J2 model) using the coupled cluster method (CCM) in high orders of approximation. We have calculated the ground state energy, the sublattice magnetization, the spin stiffness and generalized susceptibilities. We determine the quantum critical points for both the semiclassical Néel and collinear phase as J2c1≈ 0.43J1 and J2c2≈ 0.62J1 respectively, which is in good agreement with the results obtained by other approximations. Based on susceptibilities which are related to valence-bond crystal order parameters we also discuss the nature of the quantum disordered phase separating the two semiclassical phases.