Dielectric Response and Electric-Field-Induced Metastable State in an Organic Conductor β-(meso-DMBEDT-TTF)2PF6

Abstract

Dielectric response and nonlinear conduction are studied in an organic conductor β-( meso -DMBEDT-TTF) 2 PF 6 , 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 100 K. 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.