Gate-Induced Thermally Stimulated Current on the Ferroelectric-like Dielectric Properties of (BEDT-TTF)(TCNQ) Crystalline Field Effect Transistor

Masatoshi Sakai,Hiroshi Yamauchi,Shigekazu Kuniyoshi,Masakazu Nakamura,Mitsutoshi Hanada,Kazuhiro Kudo

doi:10.3390/cryst2030730

Masatoshi Sakai, Hiroshi Yamauchi + Show 4 more

Open Access

https://doi.org/10.3390/cryst2030730

Copy DOI

Abstract

A gate-induced thermally stimulated current (TSC) on β′-(BEDT-TTF)(TCNQ) crystalline FET were conducted to elucidate the previously observed ferroelectric-like behaviors. TSC which is symmetric for the polarization of an applied VPG and has a peak at around 285 K was assigned as a pyroelectric current. By integrating the pyroelectric current, temperature dependence of the remnant polarization charge was obtained and the existence of the ferroelectric phase transition at 285 K was clearly demonstrated. We have tentatively concluded that the phase transition between dimer Mott insulator and charge ordered phase occurred at around the interface of organic crystal and substrate.

Highlights

Electronic ferroelectricity derived from charge ordered phase attract much attention in the wide range of the research area
By the measurement of the temperature dependence and applied gate voltage dependence of gate capacitance included in a field effect transistor (FET) structure, we have found out that a ferroelectric-like transition exists in β 0 - (BEDTTTF)(TCNQ)
We have presented the gate-induced thermally stimulated current (TSC) experiment on (BEDT-TTF)(TCNQ) crystalline FET sample to elucidate previously observed ferroelectric-like behaviors and related abrupt change of the field effect carrier mobility

Summary

Introduction

Electronic ferroelectricity derived from charge ordered phase attract much attention in the wide range of the research area. The carrier patterns make large coherent domains in low temperature [1,2,3,4,5,6] Since this is a kind of an electrically polarized electronic state, the charge distribution is modulated by an external electric field with increasing temperature. In these days, it is recognized that several types of organic correlated electronic materials exhibit electronic ferroelectricity. By the measurement of the temperature dependence and applied gate voltage dependence of gate capacitance included in a FET structure, we have found out that a ferroelectric-like transition exists in β 0 - (BEDTTTF)(TCNQ). By measuring a pyroelectric current, the existence of spontaneous polarization which is the origin of the observed ferroelectric-like behavior is experimentally demonstrated

Experimental Details

Results and Discussion

Conclusions