Dielectric response and electric-field-induced metastable state in an organic conductor β-(meso-DMBEDT-TTF)2PF6

Dielectric response and nonlinear conduction are studied in an organic conductor beta-(meso-DMBEDT-TTF)(2)PF6, which undergoes the metal-insulator transition caused by the checkerboard-type charge ordering (CCO). The formation of the long-range CCO (LR-CCO) was observed as a sudden increase in the dielectric constant below 70 K. Below 70 K, the I-V curve shows a remarkable negative differential resistance with a non-monotonous voltage drop, and its nonlinearity survives up to about 100K. Time-resolved sample voltage data shows a steep drop followed by a transient plateau and a further drop into the most conductive state. The former steep voltage drop may cause the negative differential resistance in the I-V curve, while the transient plateau implies a metastable state induced by the electric field.