Electric field-driven resistive transitions in correlated CuIr₂S₄

CuIr₂S₄ is a strongly correlated material wherein intricate entanglement of electronic degrees of freedoms makes it sensitive to external stimuli resulting in an emergent phenomenon such as metal-insulator transition at T_c ~ 231 K. Below T_c, a hysteretic resistive transition from an insulating to a metallic phase can be induced by sweeping electric field across the sample. The nature of the switching changes from an abrupt jump in current-voltage characteristics away from T_c to step-like jumps near T_c. The electrically-driven transition is studied using electrical transport, resistance noise spectroscopy, and a nonequilibrium free-energy model, where effective temperature of charge carriers is defined as a function of local electric field. Normalized power spectral density (PSD) of resistance fluctuations show distinct features at temperatures far away and near T_c, and the behavior of normalized PSD is reproduced well in theoretical simulation. Spontaneous segregation of phases near T_c and their evolution in response to electrical bias appear to have an impact on charge transport near the transition. The noise behavior observed in CuIr₂S₄ can be seen in other materials and it points towards a common origin to phase separation near transition in strongly correlated materials.