Chin Hao-Ting, Klimes Jiri, Hu I-Fan, Chen Ding-Rui, Nguyen Hai-Thai, Chen Ting-Wei, Ma Shao-Wei, Hofmann Mario, Liang Chi-Te, Hsieh Ya-Ping
Institute for Atomic and Molecular Science, Academia Sinica, Taipei, 10617, Taiwan.
International Graduate Program of Molecular Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.
Nat Commun. 2021 Nov 1;12(1):6291. doi: 10.1038/s41467-021-26589-x.
We here report on the direct observation of ferroelectric properties of water ice in its 2D phase. Upon nanoelectromechanical confinement between two graphene layers, water forms a 2D ice phase at room temperature that exhibits a strong and permanent dipole which depends on the previously applied field, representing clear evidence for ferroelectric ordering. Characterization of this permanent polarization with respect to varying water partial pressure and temperature reveals the importance of forming a monolayer of 2D ice for ferroelectric ordering which agrees with ab-initio and molecular dynamics simulations conducted. The observed robust ferroelectric properties of 2D ice enable novel nanoelectromechanical devices that exhibit memristive properties. A unique bipolar mechanical switching behavior is observed where previous charging history controls the transition voltage between low-resistance and high-resistance state. This advance enables the realization of rugged, non-volatile, mechanical memory exhibiting switching ratios of 10, 4 bit storage capabilities and no degradation after 10,000 switching cycles.
我们在此报告对二维相水冰铁电特性的直接观测。在两层石墨烯之间进行纳米机电限制时，水在室温下形成二维冰相，该相表现出一个强且永久的偶极子，其取决于先前施加的电场，这是铁电有序的明确证据。关于不同水蒸气压和温度对这种永久极化的表征揭示了形成二维冰单层对于铁电有序的重要性，这与进行的从头算和分子动力学模拟结果一致。观测到的二维冰强大的铁电特性使得新型纳米机电器件具备忆阻特性成为可能。观察到一种独特的双极机械开关行为，其中先前的充电历史控制着低电阻和高电阻状态之间的转变电压。这一进展使得能够实现坚固耐用、非易失性的机械存储器，其开关比为10，具备4比特存储能力，并且在10000次开关循环后无退化现象。
