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08:43
Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors
Published on: November 7, 2016
Current-voltage characteristics of charge-ordered organic crystals
Yamaguchi Takahide1, Takako Konoike, Kengo Enomoto
1National Institute for Materials Science, Tsukuba 305-0003, Japan.
Physical Review Letters
|May 23, 2006
Summary
Layered organic crystals exhibit power-law current-voltage behavior in their insulating state. This is due to electric field-induced electron-hole pair unbinding, revealing long-range Coulomb interactions.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Organic Electronics
Background:
- Layered organic crystals, specifically theta-(BEDT-TTF)2MZn(SCN)4 (M = Cs, Rb), are studied in their low-temperature insulating state.
- Understanding charge transport mechanisms in these materials is crucial for developing novel electronic devices.
Purpose of the Study:
- To investigate the current-voltage (I-V) characteristics of theta-(BEDT-TTF)2MZn(SCN)4 crystals.
- To elucidate the underlying physical mechanisms responsible for the observed I-V behavior.
- To determine the nature and range of electron-electron Coulomb interactions in these organic conductors.
Main Methods:
- Electrical transport measurements were performed on theta-(BEDT-TTF)2MZn(SCN)4 crystals at low temperatures (down to 0.29 K).
- Current-voltage characteristics were analyzed over a wide range of currents to identify deviations from Ohmic behavior.
- The observed power-law exponents and crossover electric fields were used to infer interaction parameters.
Main Results:
- The current-voltage characteristics follow a power law with a large exponent (e.g., 8.4 at 0.29 K for M = Cs) in the low-temperature insulating state.
- Power-law behavior is attributed to electric field-induced unbinding of thermally excited electron-hole pairs within a two-dimensional charge-ordered background.
- Crossover electric fields indicate that electron-electron Coulomb interactions are significantly long-ranged, with a screening length exceeding 10 molecular sites.
Conclusions:
- The study reveals a distinct non-Ohmic transport mechanism in layered organic crystals governed by electric field-induced charge carrier unbinding.
- The findings highlight the importance of long-range Coulomb interactions in dictating charge transport properties in these materials.
- This work provides fundamental insights into the electronic properties of organic conductors, relevant for advanced electronic applications.
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