Metal-insulator transition in 1T-TaS2-xSex

The transition metal dichalcogenide, 1T-TaS2, shows metal-insulator transition (MIT) accompanying the nearly commensurate (NC)-commensurate (C) charge density wave (CDW) phase transition at 180 K. It has been proposed that the low-temperature C-CDW phase is a Mott insulator. However, our specific heat and magnetic susceptibility measurements in the 1 T-Ta2 - xSex system revealed no indications of effective mass enhancement or intrinsic localized spins in the insulating phase. So we propose a new model for the MIT in which the interlayer coupling of the CDW superstructure plays an important role. (C) 2000 Published by Elsevier Science B.V. All rights reserved.