发表机构
Morgan State University（摩根州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过厚度调控与光辅助界面能带工程，揭示了超薄CuCrP2S6中铁电性与离子输运的拮抗机制，实现了铁电开关与Cu+迁移主导的忆阻行为之间的可控转变。
AI 中文摘要
超薄范德华（vdW）化合物 CuCrP2S6（CCPS）在环境温度下同时具备铁电性、光电导性和离子输运特性，这为多功能电子、光子及神经形态应用提供了巨大潜力。然而，当铁电性和离子输运共享共同的原子起源（如 CCPS 中的铜离子）时，它们可能变得相互拮抗。我们通过静电和光辅助界面能带调控，系统研究 CCPS 二极管中铁电性、离子迁移和忆阻行为的厚度依赖演化，从而解决这一基本矛盾。利用压电力显微镜、开尔文探针和导电原子力显微镜，结合光激发输运测量，我们识别出不同的厚度区间。厚度小于约 40 nm 的 CCPS 薄片表现出稳健、可逆的铁电（FE）开关。相反，较厚的样品表现出可切换极化被抑制，电传导由 Cu+ 迁移主导，并伴随丝状忆阻开关和整流反转。光照明进一步通过光生载流子增强离子迁移率，在非铁电薄片中驱动光辅助离子输运，并在铁电薄片中引发耦合的光-铁电-离子响应。这些发现阐明了铁电性如何从根本上改变 vdW 铁离子系统中离子输运动力学。
英文摘要
Ambient-temperature coexistence of ferroelectricity, photoconductivity, and ionic transport in ultra-thin van der Waals (vdW) compound CuCrP2S6 (CCPS) offers significant potential for multifunctional electronic, photonic, and neuromorphic applications. However, ferroelectricity and ionic transport can become antagonistic when sharing a common atomic origin, like the copper ions in CCPS. We address this fundamental dichotomy by systematically investigating the thickness-dependent evolution of ferroelectricity, ionic migration, and memristive behavior in CCPS diodes via electrostatic and photo-assisted interfacial band tuning. Using piezoresponse, Kelvin probe, and conductive atomic force microscopy, alongside photoexcited transport measurements, we identify distinct thickness regimes. CCPS flakes thinner than ~ 40 nm exhibit robust, reversible ferroelectric (FE) switching. Conversely, thicker samples display suppressed switchable polarization, with electrical conduction dominated by Cu+ migration, filamentary memristive switching, and rectification reversal. Optical illumination further enhances ionic mobility via photogenerated carriers, driving photo-assisted ionic transport in non-FE flakes and a coupled photoferroionic response in FE flakes. These findings clarify how ferroelectricity fundamentally alters ionic transport dynamics in vdW ferroionic systems.
CommentsSupplementary Material is included with the main manuscript. The main manuscript includes 6 figures
