Semi- OT Abstract-Graphene–ferroelectric metadevices for nonvolatile memory and reconfigurable logic-gate operations

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  Woo Young Kim,
• Hyeon-Don Kim,
• Teun-Teun Kim,
• Hyun-Sung Park,
• Kanghee Lee,
• Hyun Joo Choi,
• Seung Hoon Lee,
• Jaehyeon Son,
• Namkyoo Park
• & Bumki Min
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  • http://www.nature.com/ncomms/2016/160127/ncomms10429/abs/ncomms10429.html

Memory metamaterials are artificial media that sustain transformed electromagnetic properties without persistent external stimuli. Previous memory metamaterials were realized with phase-change materials, such as vanadium dioxide or chalcogenide glasses, which exhibit memory behaviour with respect to electrically/optically induced thermal stimuli. However, they require a thermally isolated environment for longer retention or strong optical pump for phase-change. Here we demonstrate electrically programmable nonvolatile memory metadevices realised by the hybridization of graphene, a ferroelectric and meta-atoms/meta-molecules, and extend the concept further to establish reconfigurable logic-gate metadevices. For a memory metadevice having a single electrical input, amplitude, phase and even the polarization multi-states were clearly distinguishable with a retention time of over 10 years at room temperature. Furthermore, logic-gate functionalities were demonstrated with reconfigurable logic-gate metadevices having two electrical inputs, with each connected to separate ferroelectric layers that act as the multi-level controller for the doping level of the sandwiched graphene layer.