利用可印刷六方氮化硼离子凝胶实现外延Bi (111)薄膜的门可调电子性质
Gate-tunable electronic properties of epitaxial Bi (111) films using a printable hexagonal boron nitride ionogel
AI总结：
本研究采用可印刷六方氮化硼离子凝胶实现外延Bi (111)薄膜的低压顶栅调控，发现其电子输运存在非刚性带响应，确立了该离子凝胶门控可有效调控拓扑半金属多带输运的方法。
AI中文摘要：
实现半金属中载流子输运的有效静电调控仍具挑战，原因在于强屏蔽效应与多带效应。本研究采用可印刷六方氮化硼（hexagonal boron nitride，h-BN）离子凝胶，实现了在GaAs (111)衬底上生长的外延Bi (111)薄膜中电子输运的高效低压顶栅调控。磁输运测量显示，多带电子与空穴贡献产生了显著的非线性霍尔电导率。值得注意的是，施加小于0.4 V的小栅极电压，会导致低场霍尔电导率斜率与电子-空穴补偿点发生系统演化，且该栅压响应依赖于薄膜厚度与温度。观测到的行为无法用刚性带的常规费米能级移动解释，反而表明存在与多带效应及门可调Rashba自旋轨道耦合相关的非刚性带响应。本研究结果确立了可印刷离子凝胶门控作为调控拓扑半金属中多带输运的有效方法。
英文摘要：
Achieving effective electrostatic control of carrier transport in semimetals remains challenging due to strong screening and multiband effects. We report efficient low voltage top gated control of electronic transport in epitaxial Bi (111) thin films grown on GaAs (111) substrates using a printable hexagonal boron nitride ionogel. Magnetotransport measurements reveal pronounced nonlinear Hall conductivities arising from multiband electron and hole contributions. Remarkably, the application of a small gate voltage (less than 0.4 V in magnitude) leads to a systematic evolution of the low field Hall conductivity slope and the electron-hole compensation point. The response to gate voltage depends upon thickness and temperature. The observed behavior cannot be explained by a conventional Fermi level shift with rigid bands and instead indicates a non rigid band response associated with multiband effects and a gat tunable Rashba spin orbit coupling. Our results establish printable ionogel gating as a powerful approach to tune multiband transport in topological semimetals.
