TY - JOUR
T1 - Spin-liquid state in an organic spin-1/2 system on a triangular lattice, EtMe3Sb[Pd(dmit)2]2
AU - Itou, T.
AU - Oyamada, A.
AU - Maegawa, S.
AU - Tamura, M.
AU - Kato, R.
PY - 2007/4/11
Y1 - 2007/4/11
N2 - The series of [Pd(dmit)2] salts (dmit ≤ 1,3-dithiole-2- thione-4,5-dithiolate) is a Mott insulator on an anisotropic triangular lattice and has an antiferromagnetic exchange constant J∼ 200 K. While it has been revealed that most of them undergo antiferromagnetic transitions, the nature of the spin state of EtMe3Sb[Pd(dmit)2]2 which has a nearly isotropic triangular lattice is still unknown. We investigated the spin state by means of 13C NMR measurements down to 1.37K for polycrystalline samples in which the carbon atoms in both ends of the Pd(dmit)2 molecule were selectively enriched with the 13C isotope. Both behaviours of the spin-lattice relaxation rate and the spectra indicate no spin ordering/freezing at least down to 1.37K, which is lower than one-hundredth of the exchange interaction. Furthermore, the spin-lattice relaxation rate does not show an exponential temperature dependence and seems to retain a finite value at low temperatures. Thus, the ground state of this system is possibly the almost-gapless spin-liquid state.
AB - The series of [Pd(dmit)2] salts (dmit ≤ 1,3-dithiole-2- thione-4,5-dithiolate) is a Mott insulator on an anisotropic triangular lattice and has an antiferromagnetic exchange constant J∼ 200 K. While it has been revealed that most of them undergo antiferromagnetic transitions, the nature of the spin state of EtMe3Sb[Pd(dmit)2]2 which has a nearly isotropic triangular lattice is still unknown. We investigated the spin state by means of 13C NMR measurements down to 1.37K for polycrystalline samples in which the carbon atoms in both ends of the Pd(dmit)2 molecule were selectively enriched with the 13C isotope. Both behaviours of the spin-lattice relaxation rate and the spectra indicate no spin ordering/freezing at least down to 1.37K, which is lower than one-hundredth of the exchange interaction. Furthermore, the spin-lattice relaxation rate does not show an exponential temperature dependence and seems to retain a finite value at low temperatures. Thus, the ground state of this system is possibly the almost-gapless spin-liquid state.
UR - http://www.scopus.com/inward/record.url?scp=33947678788&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/19/14/145247
DO - 10.1088/0953-8984/19/14/145247
M3 - Article
AN - SCOPUS:33947678788
SN - 0953-8984
VL - 19
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 14
M1 - 145247
ER -