双层石墨烯中可切换的巨量室温非线性霍尔效应
Switchable giant room-temperature nonlinear Hall effect in Bilayer Graphene
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中文总结 AI 辅助
该研究在双离子栅控双层石墨烯器件中观测到可切换的巨量室温非线性霍尔效应，其性能远超同类室温器件，为无结非线性技术提供了理想平台。
中文摘要 AI 辅助
将量子二阶非线性输运应用于实用无结器件需要材料在室温下具有大且可调控的非线性，这是当前材料平台面临的挑战。在此，我们报道了双离子栅控双层石墨烯器件中的非线性霍尔效应（NLHE），该器件能实现异常强的反演对称性破缺。我们观察到可轻易切换（开启、关闭及符号反转）的NLHE，其二阶非线性 susceptibility χ⁽²⁾_{yxx}达到了巨量室温值3×10⁻³ μm S/V，与低温下WTe₂或石墨烯基莫尔超晶格中常见的值相当，比近期用于寻找室温NLHE的材料体系中报道的值大三至四个数量级。我们的器件产生了对应的太赫兹电压响应率≈4×10⁴ V/W，与商用肖特基二极管相当，比此前报道的室温NLHE器件高出数个数量级，使双离子栅控双层石墨烯成为无结非线性技术的理想平台。
英文摘要
Utilizing quantum second-order nonlinear transport for practical junction-free devices require materials with large and tunable nonlinearites at room temperature -- a current materials platform challenge. Here, we report the nonlinear Hall effect (NLHE) in double-ionic gated bilayer graphene devices that enable unusually strong inversion breaking. We observe NLHE that are readily switchable (on, off, and sign reversed) with second order nonlinear susceptibilities $χ^{(2)}_{yxx}$ that reaches giant room-temperature values of $3\,10^{-3}\,μ\mathrm{m}\,\mathrm{S/V}$, comparable to values commonly observed at low temperature in WTe$_2$ or in graphene-based moiré superlattices, and three-to-four orders of magnitude larger than values reported in material systems recently employed in search of a room-temperature NLHE. Our devices produce corresponding THz voltage responsivities $\simeq 4\,10^{4}\,\mathrm{V/W}$, comparable to commercially available Schottky diodes. These are orders of magnitude better than for previously reported room-temperature NLHE devices rendering double-ionic gated bilayer graphene a choice platform for junction-free nonlinear technology.
