Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Correlated Electrons - Poster Session
TT 20.38: Poster
Mittwoch, 28. März 2007, 14:00–17:45, Poster A
Spin liquid ground state in the frustrated S=1/2 square lattice compound PbVO3 — Alexander Tsirlin1,2, Roman Shpanchenko2, Evgeny Antipov2, Alexei Belik3, Eiji Takayama-Muromachi3, and •Helge Rosner1 — 1MPI CPfS, Dresden, Germany — 2Department of Chemistry, MSU, Russia — 3NIMS, Tsukuba, Japan
The S=1/2 square lattice is known to be one of the simplest models of low-dimensional spin systems depicting the magnetic properties of many transition metal compounds like La2CuO4. If one considers nearest-neighbor (NN) interactions only, long-range spin order is established in the square lattice. Nevertheless, taking into account next-nearest neighbor (NNN) interactions may result in strong frustration of the spin system and give rise to unusual collinear magnetic order or spin liquid ground states. Here, we present a joint experimental and computational study of a novel layered vanadium oxide PbVO3 realizing a square lattice of magnetic V+4 atoms. Our results show that in PbVO3 antiferromagnetic NN (J1) as well as NNN (J2) interactions are present. The J2/J1 ratio is about 0.3 corresponding to a boundary between AFM ordered and spin liquid ground states. This conclusion is in a perfect agreement with magnetic susceptibility and specific heat measurements showing no sign of long-range spin order down to 2 K. PbVO3 is likely to be the first system showing spin liquid ground state for the frustrated S=1/2 square lattice.
The Alfred Toepfer Foundation and the Emmy-Noether program are acknowledged for financial support.