标题： 层间耦合诱导的量子反常霍尔多层中的量子相变 显示英文标题

标题： Interlayer Coupling-Induced Quantum Phase Transition in Quantum Anomalous Hall Multilayers

摘要： 量子相变源于不同基态之间的竞争，通常通过在接近绝对零度的温度下改变单一物理参数来实现。最近，在磁性拓扑绝缘体（TI）多层结构中实现了具有高陈数C的量子异常霍尔（QAH）效应。 在这项工作中，我们采用分子束外延技术，通过改变中间磁性TI层的厚度（指定为m个五层），合成了一系列磁性TI五层结构。 电输运测量显示了C=1和C=2 QAH状态之间存在量子相变。 对于m=1和m=2，样品分别表现出清晰量化为C=1和C=2的QAH状态。 对于1 < m < 2，随着m的增加，观察到霍尔电阻从h/e²单调减小至h/2e²，并伴随着纵向电阻峰值的出现。 C=1和C=2 QAH状态之间的量子相变归因于顶部和底部C=1 QAH层之间层间耦合的减弱。 我们的发现为设计具有可调陈数的QAH器件提供了一种可扩展的策略。这种方法能够在手征边缘电流为基础的电子器件中实现精确控制和增强的功能。 显示英文摘要

摘要： A quantum phase transition arises from competition between different ground states and is typically accessed by varying a single physical parameter near absolute zero temperature. The quantum anomalous Hall (QAH) effect with high Chern number C has recently been achieved in magnetic topological insulator (TI) multilayers. In this work, we employ molecular beam epitaxy to synthesize a series of magnetic TI penta-layers by varying the thickness of the middle magnetic TI layer, designated as m quintuple layers. Electrical transport measurements demonstrate a quantum phase transition between C = 1 and C = 2 QAH states. For m 1 and m 2, the sample exhibits the well-quantized C = 1 and C = 2 QAH states, respectively. For 1 m 2, we observe a monotonic decrease in Hall resistance from h/e2 to h/2e2 with increasing m, accompanied by a peak in the longitudinal resistance. The quantum phase transition between C = 1 and C = 2 QAH states is attributed to the weakening of the interlayer coupling between the top and the bottom C = 1 QAH layers. Our findings provide a scalable strategy for engineering QAH devices with a tunable Chern number. This approach enables precise control and enhanced functionality in chiral edge current-based electronic devices.