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Orbital-Peierls State in NaTiSi2O6

Jasper van Wezel·Jeroen van den Brink
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Abstract

Does the quasi one-dimensional titanium pyroxene NaTiSi2O6 exhibit the novel {\it orbital-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 quantum fluctuations in the spin-orbital sector drive the transition, explaining why canonical bandstructure methods fail to find it. The conclusion that NaTiSi2O6 shows an orbital-Peierls transition is therefore inevitable.

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Jasper van Wezel, Jeroen van den Brink. 2005-12-23. Orbital-Peierls State in NaTiSi2O6. https://doi.org/10.1209/epl%2Fi2006-10197-2

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