Large negative magnetoresistance induced by anionic solid solutions in two-dimensional spin-frustrated transition metal chalcogenides.

We report an anionic solid solution process that induces frustrated magnetic structures within two-dimensional transition metal chalcogenides, which leads to huge negative magnetoresistance effects. Ultrathin nanosheets of TiTe(2-x)I(x) solid solutions, which are a new class of inorganic two-dimensional magnetic material, exhibit negative magnetoresistance with a value of up to -85%, due to the spin-dependent scattering effects of local Ti(3+) 3d(1) moments that are antiferromagnetically coupled. Moreover, TiTe(2-x)I(x) serials show unique transport behaviors with continuous evolution from metallic to semiconducting states. We anticipate that anionic doping will be a powerful tool for optimizing the intrinsic physical properties of two-dimensional transition metal chalcogenide system.