Neuromorphic computational systems that emulate biological synapses in the human brain are fundamental in the development of artificial intelligence protocols beyond the standard von Neumann architecture. Such systems require new types of building blocks, such as memristors that access a quasi-continuous and wide range of conductive states, which is still an obstacle for the realization of high-efficiency and large-capacity learning in neuromorphoric simulation. Here, we introduce hydrogen and sodium titanate nanobelts, the intermediate products of hydrothermal synthesis of TiO₂ nanobelts, to emulate the synaptic behavior. Devices incorporating a single titanate nanobelt demonstrate robust and reliable synaptic functions, including excitatory postsynaptic current, paired pulse facilitation, short term plasticity, potentiation and depression, as well as learning-forgetting behavior. In particular, the gradual modulation of conductive states in the single nanobelt device can be achieved by a large number of identical pulses. The mechanism for synaptic functionality of the titanate nanobelt device is attributed to the competition between an electric field driven migration of oxygen vacancies and a thermally induced spontaneous diffusion. These results provide insight into the potential use of titanate nanobelts in synaptic applications requiring continuously addressable states coupled with high processing efficiency.

中文翻译：

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单个钛酸酯纳米带中的氧空位迁移/扩散引起的突触可塑性†

模拟人脑中生物突触的神经形态计算系统是超越标准冯·诺依曼（von Neumann）体系结构的人工智能协议开发的基础。这样的系统需要新型的构造块，例如访问准连续和宽范围导电状态的忆阻器，这仍然是在神经形态模拟中实现高效和大容量学习的障碍。在这里，我们介绍氢和钛酸钠纳米带，水热合成TiO ₂的中间产物纳米带，模仿突触行为。包含单个钛酸酯纳米带的设备显示出强大而可靠的突触功能，包括兴奋性突触后电流，成对的脉冲促进，短期可塑性，增强和抑制以及忘记学习的行为。特别地，可以通过大量相同的脉冲来实现单个纳米带装置中的导电状态的逐渐调制。钛酸酯纳米带装置的突触功能的机理归因于电场驱动的氧空位迁移与热诱导的自发扩散之间的竞争。这些结果提供了钛酸盐纳米带在需要连续可寻址状态以及高处理效率的突触应用中的潜在用途的见识。