Kazuya MIYAGAWA, Atsushi KAWAMOTO (Ochanomizu Univ.) and Kazushi KANODA
[Phys. Rev. B 56 (1997) in press]
The low-temperature nesting instability in the quasi-two-dimensional organic conductor, (alpha)-(BEDT-TTF)2RbHg(SCN)4, has been investigated by 13C NMR. Below 12 K, drastic decreases in the Knight shift and 1/(T1T)-1 were observed with neither splitting nor broadening in the NMR spectra, as shown in Figures. 1 and 2. The 1/(T1T)-1 shows no enhancement around the nesting instability, unlike the conventional spin-density-wave (SDW) transition. The present 13C NMR data are suggestive of nonmagnetic transition but allow only an unusual case of mobile state in the SDW scenario.
Figure 1. (a) 13C NMR spectra and (b) averaged Knight shift of a single crystal under a perpendicular field of 8 T.
Figure 2. 13C nuclear spin-lattice relaxation rate. The low-temperature region is expanded in the inset.