Paramagnetic Susceptibility of 1T-TaS₂ and 1T-TaS_1.7Se_0.3 in Aderson Localized States

抄録

The low temperature paramagnetism of 1T-TaS₂ has been confirmed to be due to Anderson localization by measuring the magnetic susceptibility of 1T-TaS₂ and 1T-TaS_1.7Se_0.3 whose crystalline defects were controlled by annealing. The data are well fitted to a Curie-Weiss equation, and the concentrations of localized spins decrease with an increase of annealing time. The magnitude and the sign of paramagnetic Curie temperature are sample-dependent and take both positive and negative values of −2.1 K to 4.8 K.
The correlation energy, U of the Coulomb repulsive interaction when two electrons with the opposite spin occupy the same localized state is estimated to be 140 K for the 1T-TaS₂ single crystal.