Redistribution of Charge in the Proximity of the Spin-Peierls Transition: ¹³C NMR Investigation of (TMTTF)₂PF₆

Abstract

¹³C nuclear magnetic resonance (NMR) investigations were carried out for a one-dimensional organic conductor, (TMTTF)₂PF₆, to determine the charge dynamics and configuration in the proximity of the spin-Peierls phase-transition temperature, T_sP. Although no obvious NMR line splitting associated with the charge-ordering transitions in the intermediate paramagnetic states was observed, the charge separation amplitude was estimated to be ρ_CO∼0.14 using the ¹³C NMR spin–lattice relaxation rates for the distinct lines. The abrupt decrease in the NMR linewidth below 25 K and the small anisotropy of the NMR linewidth in the spin-Peierls phase indicate the possible redistribution of the charge separation in the proximity of T_sP. The low-temperature electronic states of (TMTTF)₂PF₆ are discussed from a microscopic point of view.