The persistent and switchable polarization of ferroelectric materials based on HfO$_2$-based ferroelectric compounds, compatible with large-scale integration, are attractive synaptic elements for neuromorphic computing. To achieve a record current density of 0.01 A/cm$^2$ (at a read voltage of 80 mV) as well as ideal memristive behavior (linear current-voltage relation and analog resistive switching), devices based on an ultra-thin (2.7 nm thick), polycrystalline HfZrO$_4$ ferroelectric layer are fabricated by Atomic Layer Deposition. The use of a semiconducting oxide interlayer (WO$_{x<3}$) at one of the interfaces, induces an asymmetric energy profile upon ferroelectric polarization reversal and thus the long-term potentiation / depression (conductance increase / decrease) of interest. Moreover, it favors the stable retention of both the low and the high resistive states. Thanks to the low operating voltage (<3.5 V), programming requires less than 10${^-12}$ J for 20 ns long pulses. Remarkably, the memristors show no wake-up or fatigue effect.

翻译：基于HfO$_2$铁电化合物的铁电材料具有持久且可切换的极化特性，且兼容大规模集成，是神经形态计算中极具吸引力的突触元件。为获得创纪录的0.01 A/cm$^2$电流密度（在80 mV读取电压下）以及理想的忆阻行为（线性电流-电压关系和模拟电阻开关），本研究利用原子层沉积技术制备了基于超薄（2.7 nm厚）多晶HfZrO$_4$铁电层的器件。在其中一个界面处引入半导体氧化物中间层（WO$_{x<3}$），可在铁电极化反转时诱导出不对称能垒分布，从而实现所需的长时程增强/抑制（电导增加/减少）。此外，该中间层有助于稳定保持低阻态和高阻态。得益于低工作电压（<3.5 V），20 ns脉冲的编程能耗低于10${^-12}$ J。值得注意的是，该忆阻器未表现出唤醒效应或疲劳效应。