论文标题
交换偏见的量子异常效应
Exchange-biased quantum anomalous Hall effect
论文作者
论文摘要
量子异常霍尔（QAH）效应的特征是无耗散的手性边缘状态，在零磁场处具有量化的霍尔电阻。在理解拓扑量子物理和实施无耗散电子设备方面，操纵QAH状态至关重要。在这里，我们意识到磁性拓扑绝缘子CR掺杂（BI，SB）2TE3（CBST）在未补偿的抗铁磁绝缘子Al掺杂CR2O3上生长的QAH效应。通过偏振中子反射测定法（PNR），我们发现CBST和Al-Cr2O3表面旋转之间的强烈交换耦合固定垂直于膜平面的界面磁矩。界面耦合会产生交换偏置的QAH效应。我们进一步证明，可以使用现场训练过程有效控制交换偏置的幅度和符号，以设置Al-Cr2O3层的磁化。我们的工作证明了使用交换偏见效应有效地操纵QAH状态，从而在基于QAH的Spintronics中开放了新的可能性。
The quantum anomalous Hall (QAH) effect is characterized by a dissipationless chiral edge state with a quantized Hall resistance at zero magnetic field. Manipulating the QAH state is of great importance in both the understanding of topological quantum physics and the implementation of dissipationless electronics. Here, we realized the QAH effect in the magnetic topological insulator Cr-doped (Bi,Sb)2Te3 (CBST) grown on an uncompensated antiferromagnetic insulator Al-doped Cr2O3. Through polarized neutron reflectometry (PNR), we find a strong exchange coupling between CBST and Al-Cr2O3 surface spins fixing interfacial magnetic moments perpendicular to the film plane. The interfacial coupling results in an exchange-biased QAH effect. We further demonstrate that the magnitude and sign of the exchange bias can be effectively controlled using a field training process to set the magnetization of the Al-Cr2O3 layer. Our work demonstrates the use of the exchange bias effect to effectively manipulate the QAH state, opening new possibilities in QAH-based spintronics.
