Electrical Manipulation of Topological Phases in a Quantum Anomalous Hall Insulator
Electrical Manipulation of Topological Phases in a Quantum Anomalous Hall Insulator
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DOI：
10.1002/adma.202207622
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发表时间：
2023-02-08
影响因子：
29.4
通讯作者：
Wang, Kang. L.
中科院分区：
文献类型：
--
作者：
Chong, Su Kong;Zhang, Peng;Wang, Kang. L.
磁掺杂拓扑绝缘体中反转带拓扑引起的量子反常霍尔相已成为零磁场下量子化研究的一个重要课题。分子束外延（MBE）生长的量子反常霍尔物质的复杂电气控制虽然是实际实现所必需的，但由于生长和制造方面的挑战，一直受到阻碍。本文展示了一种新的方法，利用薄膜沉积和二维材料堆叠技术相结合，创建了mbe生长的量子反常霍尔绝缘体，cr掺杂（Bi,Sb）(2)Te-3的双门控器件。在这些装置中，证明了场感应电荷密度和电位移场的正交控制。详细研究了材料对沿控制轴调谐的响应，实现了沿控制轴的磁性能控制和沿控制轴操纵表面交换间隙的新能力。通过电处理交换间隙，证明了增强量子反常霍尔态或完全抑制量子反常霍尔态并驱动拓扑相变到平凡态的能力。用第一性原理理论计算解释了实验结果，并为量子反常霍尔态和拓扑的原位控制建立了一条实用的途径。
Quantum anomalous Hall phases arising from the inverted band topology in magnetically doped topological insulators have emerged as an important subject of research for quantization at zero magnetic fields. Though necessary for practical implementation, sophisticated electrical control of molecular beam epitaxy (MBE)-grown quantum anomalous Hall matter have been stymied by growth and fabrication challenges. Here, a novel procedure is demonstrated, employing a combination of thin-film deposition and 2D material stacking techniques, to create dual-gated devices of the MBE-grown quantum anomalous Hall insulator, Cr-doped (Bi,Sb)(2)Te-3. In these devices, orthogonal control over the field-induced charge density and the electric displacement field is demonstrated. A thorough examination of material responses to tuning along each control axis is presented, realizing magnetic property control along the former and a novel capability to manipulate the surface exchange gap along the latter. Through electrically addressing the exchange gap, the capabilities to either strengthen the quantum anomalous Hall state or suppress it entirely and drive a topological phase transition to a trivial state are demonstrated. The experimental result is explained using first principle theoretical calculations, and establishes a practical route for in situ control of quantum anomalous Hall states and topology.