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Article Dans Une Revue Journal of Physical Chemistry C Année : 2015

Resistive Switching Induced by Electric Pulses in a Single-Component Molecular Mott Insulator

Résumé

Resistive random-access memory (ReRAM) made of organic materials has recently received much attention for application in flexible devices. In the latter, resistive switching is usually obtained thanks to electrochemical effects or charge trapping. This work shows that, under electric pulses, the crystalline molecular Mott insulator [Au(Et-thiazdt) 2 ] exhibits a resistive switching based on an insulator-to-metal transition (IMT). Electric pulses exceeding a threshold electric field of a few kilovolts/centimeter induce a volatile transition, due to an intrinsic, purely electronic effect related to an avalanche phenomenon. Moreover, the application of electric pulses of higher amplitude induces a nonvolatile and reversible resistive switching. Both two-level and multilevel switching between resistances R on and R off are observed. At room temperature, a R off /R on ratio >100 is obtained, which is very high for this kind of switching mechanism and quite promising for ReRAM applications. [Au(Et-thiazdt) 2 ] appears as the first molecular member of a new class of ReRAM called Mott memories. ■ INTRODUCTION The demand for organic-based electronic devices has recently increased due to their potential advantages over conventional inorganic electronics, such as their low fabrication cost, high mechanical flexibility, light weight, and ease of fabrication. 1,2 Flexible organic memories that would enable data processing, storage, and communication are essential components to achieve flexible electronics. 3−9 In that context, resistive random-access memory (ReRAM) made of organic materials has recently received much attention. 10−14 In ReRAM, information storage is enabled by a nonvolatile resistive switching between two different resistance states achieved by the application of short electric pulses. In organic ReRAM, resistive switching mechanisms generally involve electro-chemical effects associated with anion or cation migrations or charge trapping in metallic nanoparticles. 15−20 A new type of resistive switching was recently reported in several chalcogenide inorganic narrow-gap Mott insulators with formulation AM 4 Q 8 (A = Ga, Ge; M = V, Nb, Ta; Q = S, Se). 21−24 The application of short electric pulses on these compounds induces a new phenomenon of volatile and nonvolatile resistive switching related to the collapse of the Mott insulating state. The volatile transition appears above threshold electric fields of a few kilovolts/centimeter and is based on an electronic avalanche process. 22,23 For electric fields much higher than the threshold avalanche breakdown field (E th), the resistive switching turns nonvolatile. 21 The switching mechanism is closely related with their Mott insulator character, as the avalanche breakdown induces the collapse of the Mott insulating state at the local scale and triggers the formation of a granular conductive filament formed by metallic and superinsulating domains. 21−23,25 First identified in inorganic compounds, the generalization of this purely electronic intrinsic effect to organic Mott insulators could open new perspectives in organic electronics. Such compounds can be found in mixed valence, multicomponent salts derived from tetrathiafulvalenes or from metal bis(dithiolene) complexes, for example, the conducting C[M(dmit) 2 ] 2 salts (dmit = 1,3-dithiole-2-thione-4,5-dithiolate, C = TTF + , Me 4 N + , ...). 26,27 More recently, single-component molecular conductors based on neutral metal bis(dithiolene) complexes have also emerged as attractive systems devoid of any counterions. 28−30 For instance, neutral gold complexes formulated as [Au(dt) 2 ] • are radical species and can potentially behave as Mott insulators, with one radical per site. 31−33 The possible observation of a resistive switching phenomenon among such molecular compounds is addressed here. We will show, indeed, that the application of electric pulses on the neutral gold dithiolene complex [Au(Et-thiazdt) 2 ]

Domaines

Chimie organique
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Dates et versions

hal-01122400 , version 1 (04-05-2015)

Identifiants

Citer

Pablo Stoliar, Pascale Diener, Julien Tranchant, Benoît Corraze, Benjamin Brière, et al.. Resistive Switching Induced by Electric Pulses in a Single-Component Molecular Mott Insulator. Journal of Physical Chemistry C, 2015, 119, 119 (119), pp.2983-2988. ⟨10.1021/jp512810e⟩. ⟨hal-01122400⟩
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