J. van Wezel and J. van den Brink 2006 Europhys. Lett. 75 957 doi:10.1209/epl/i2006-10197-2
J. van Wezel1 and J. van den Brink1,2
Show affiliationsDoes the quasi–one-dimensional titanium pyroxene NaTiSi2O6 exhibit the novel orbital-assisted Peierls state? We calculate its groundstate properties by three methods: Monte Carlo simulations, a spin-orbital decoupling scheme and a mapping onto a classical model. The results show univocally that for the spin and orbital ordering to occur at the same temperature—an experimental observation—the crystal field needs to be small and the orbitals are active. We also find that fluctuations in the spin-orbital sector drive the transition, explaining why bandstructure methods fail to find it. The conclusion that NaTiSi2O6 shows an orbital assisted Peierls transition is therefore inevitable.
75.10.Dg Crystal-field theory and spin Hamiltonians
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
Issue 6 (September 2006)
Received 23 June 2006, accepted for publication 21 July 2006, in final form 21 July 2006
Published 9 August 2006
J. van Wezel and J. van den Brink 2006 Europhys. Lett. 75 957