Spin-peierls and antiferromagnetic transition temperatures in (TMTTF)2PF6: EPR and NMR measurements and theory
Résumé
We report on EPR measurements on (TMTTF)2PF6 which address the evolution of the spin-Peierls transition temperature Tc as a function of pressure. The line intensity was used as a probe of the magnetic susceptibility, and therefore of the density of states at the Fermi level. This density drops in the spin-Peierls regime. The extrapolated onset of the gap is used as a measurement of Tc. Using these results and previous NMR data on the antiferromagnetic transition temperature, a complete phase diagram is presented. It will be explained using a model involving an interacting electron gas coupled to acoustic phonons. The various parameters are obtained from available experimental results while their pressure and temperature dependence is suggested as a theoretical model. The interchain interactions (exchange and charge) are deduced from a fit of the transition temperature at 0 and 13 kbar. A very satisfactory phase diagram is deduced.
| Origine | Accord explicite pour ce dépôt |
|---|---|
| Licence |