J. Phys. IV France 131 (2005) 357-358
NMR evidence of hidden order in the high-temperature phase of (TaSe4)2IL. Németh1, G. Kriza1, P. Matus1 and B. Alavi2
1 Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, PO Box 49, 1525 Budapest, Hungary
2 Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547, USA
(TaSe4)2 I has a quasi-one-dimensional electronic structure with charge-density wave (CDW) ground state forming in a phase transition at TP = 265 K. Here we report on 77Se nuclear magnetic resonance (NMR) spectrum and spin-spin relaxation time (T2) measurements in the temperature range of 100 to 380 K. The line positions are shown to couple to the CDW order parameter. The spin-spin relaxation rate displays a sharp minimum at TP; signs of critical slowing down are absent. Together with the fast increase of the order parameter, these findings are consistent with a true gap due to hidden order in the high-temperature phase.
© EDP Sciences 2005