AI 中文总结
研究通过轨道选择性掺杂打破金属性与铁电性的互斥，在重氮掺杂的立方碳化硅中实现二者共存，开发出满足低功耗、高速要求的高性能铁电器件
AI 中文摘要
铁电性与金属导电性的互斥是长期存在的准则，因为巡游电子会屏蔽稳定体相极性序的长程库仑力。本研究通过对立方碳化硅（3C-SiC）这种非极性共价半导体进行重氮掺杂，打破了这一范式。这引入了重电子掺杂，诱导出金属性，并通过赝姜-泰勒效应驱动结构从非极性F-43m对称性向极性R3m对称性转变。值得注意的是，我们在铁电金属中提供了外电压偏置下约180°极化反转的直接原子级可视化。传导电子占据的反键轨道具有强定向特性，阻止了它们屏蔽局域Si-C极化，从而实现了金属性与铁电性的共存。铁电隧道结表现出非易失性存储特性，具有明确的高阻态（HRS）和低阻态（LRS）、超高响应速度（~50 ns）、超低工作电压（1 V）、超过85927次循环的 endurance，以及预计100年的保持时间。我们的结果为在金属中开拓铁电性提供了新策略，为探索奇异性质提供了新的铁电金属平台，并开发出满足低功耗、高速非易失性器件要求的高性能铁电器件。
英文摘要
The mutual exclusion of ferroelectricity and metallic conductivity is a long-standing tenet because itinerant electrons screen long-range Coulomb forces that stabilize the bulk polar order. Here, we break this paradigm by heavily doping a non-polar covalent semiconductor of cubic silicon carbide (3C-SiC) with nitrogen. This introduces heavy electron doping, inducing metallicity and driving a structural transition from the non-polar F-43m to the polar R3m symmetry via the pseudo-Jahn-Teller effect. Remarkably, we provide direct, atomic-scale visualization of about 180° polarization reversal under an external voltage bias in a ferroelectric metal. The strongly directional character of antibonding orbitals occupied by conduction electrons prevents them from screening the local Si-C polarization, resulting in the coexistence of metallicity and ferroelectricity. Ferroelectric tunnel junctions demonstrate nonvolatile memory properties with a well-defined high-resistance state (HRS) and low-resistance state (LRS), an ultrahigh response speed (~50 ns), an ultralow operating voltage (1 V), an endurance exceeding 85927 cycles, and a projected retention time of 100 years. Our results provide a novel strategy for pioneering ferroelectricity in a metal, a new ferroelectric metal platform for exploring exotic properties, and a ferroelectric device with high performance that meets the requirements for low consumption and high-speed non-volatile devices.
