Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 38: Correlated Electrons: Metal-Insulator Transition 1

TT 38.13: Talk

Wednesday, March 13, 2013, 12:45–13:00, H20

Electric-Field Induced Insulator-Metal Transition in α-(BEDT-TTF)₂I₃ — •Tobias Knoblauch¹, Tomislav Ivek^1,2, Dieter Schweitzer¹, and Martin Dressel¹ — ¹Physikalisches Institut, Universität Stuttgart, Germany — ²Institut za fiziku, Zagreb, Croatia

Over many decades electric-field induced switching phenomena have been observed in different types of materials, for example, transition metal oxides, inorganic semiconductors as well as organic conductors. In the last mentioned material class, the 2D organic salt α-(BEDT-TTF)₂I₃ is one of the model systems revealing a metal-insulator phase transition at 136 K in a charge-ordered state. We investigated the switching process in α-(BEDT-TTF)₂I₃ from the low conducting (charge-ordered) into the high conducting state triggered by a pulsed electric field in a temperature range from 120 to 133 K. The observed nonlinear current-voltage characteristics show negative differential resistance depending on temperature and on the applied electric field. As the underlying physical mechanism is still under consideration, we have performed time-dependent FTIR measurements to track the switching. It gives us, in combination with the steady-state infrared experiments, the possibility to gain more information about the processes responsible for this effect. Here, we also present possible physical models to explain the observed behavior.