Se77nuclear magnetic resonance in di-tetramethyltetraselenafulvalene phosphorous hexafluoride [(TMTSF)2PF6] under pressure

We report measurements of the Knight shift, spin-lattice relaxation time, linewidth, and absolute susceptibility of ${}_{}{}^{77}{}_{}{}^{}\mathrm{Se}$ as functions of pressure, field, and temperature in the organic super-conductor tetramethyltetraselenafulvalene phosphorous hexafluoride [${\mathrm{}\left(\mathrm{TMTSF}\right)\mathrm{}}_2$P${\mathrm{F}}_6$]. The results indicate that there is significant $p$-wave spin density at the Se sites and that the quenching of the spin-density wave (SDW) is a slow function of pressure. That is, there is a significant pressure regime where there is coexistence of a metallic and SDW state. The nature of this coexistence is discussed.