Effects of Carrier Doping into the Misfit-Layer Compounds (La_1-yR_yS)_1+αVS₂ (R=Sr and Pb): Transport and Magnetic Studies

Abstract

Transport and magnetic measurements including the magnetic resonance of ⁵¹V nuclei have been carried out for misfit-layer compounds (La_1-yR_yS)_1+αVS₂ (R=Sr and Pb, 0≤ y≤ 1.0). The results indicate that the system is in the Mott insulating state at high temperatures, at least in the y region near α /(1+α) which corresponds to the V-valency of +3. It undergoes a transition with decreasing temperature possibly to a nonmagnetic ground state. With increasing carrier doping into this insulating state, the system tends to become metallic and an essentially metallic state is realized in the hole-doped region 0.30 x ≡ y(1+α )<0.5, where various properties are found to exhibit anomalous behavior similar to the case of high-T_c Cu-oxides.