Disorder Induced Superconductivity in TiSe_1.2S_0.8

Abstract

Disorder can be utilized as an effective parameter to probe the interplay between two long range orders such as superconductivity and charge density wave. In the present work, we report on the experimental evidence for filamentary superconductivity in polycrystalline TiSe1.2S0.8 with superconducting transition Tc ~ 7K. This is validated from magnetization and magneto-transport measurements. Strain induced dislocations, substitutional defects, and randomly distributed Ti ions (with local moments) are considered as possible sources of disorder. A detailed analysis of the temperature dependent resistivity evaluates the degree of disorder and the consequent localization effects. The findings are in striking contrast to the fact that superconductivity has not been reported in single crystals of TiSe2-xSx system. It is established that disorder serves as a stabilizing factor for the superconducting phase due to in-commensuration of the charge density wave.