title: Graphene-ferroelectric metadevices for nonvolatile memory and reconfigurable logic-gate operations.
abstract: 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.
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Woo Young
authors.initials: WY
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Hyeon-Don
authors.identifier: http://orcid.org/0000-0002-9136-3442
authors.initials: HD
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.|Metamaterial Research Centre, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Teun-Teun
authors.initials: TT
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Hyun-Sung
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Kanghee
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Jaehyeon
authors.initials: J
authors.lastname: Son
authors.affiliation: Photonic Systems Laboratory, School of EECS, Seoul National University, Seoul 151-744, Republic of Korea.
authors.forename: Namkyoo
authors.identifier: http://orcid.org/0000-0003-0197-7633
authors.initials: N
authors.lastname: Park
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Bumki
authors.initials: B
authors.lastname: Min
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