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Layer-Dependent Quantum Anomalous Hall and Quantum Spin Hall Effects in Two-Dimensional LiFeTe
Yanzhao Wu1, Li Deng1, Junwei Tong2
1Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, China.
ACS Applied Materials & Interfaces
|July 24, 2024
Summary
Researchers discovered that stacking layers of LiFeTe creates tunable quantum anomalous Hall (QAH) and quantum spin Hall (QSH) effects. Layer number controls magnetic coupling and topological states in these 2D materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Physics
Background:
- The integration of topology and magnetism in low-dimensional materials is a key area of research.
- Intrinsic quantum anomalous Hall (QAH) insulators with long-range magnetic order are crucial for this field.
Purpose of the Study:
- To investigate the manipulation of magnetic coupling and topological electronic states in stacked two-dimensional (2D) LiFeTe by varying layer numbers.
- To explore the emergence of QAH and quantum spin Hall (QSH) states in relation to layer-dependent magnetic ordering.
Main Methods:
- Theoretical investigation of stacked 2D LiFeTe structures.
- Analysis of magnetic coupling (ferrimagnetic and antiferromagnetic) based on layer configurations.
- Characterization of topological electronic states, including Chern numbers and spin Chern numbers.
Main Results:
- Monolayer LiFeTe exhibits intralayer ferrimagnetic coupling and acts as a QAH insulator (Chern number C = 2).
- Odd and even layers of LiFeTe display distinct interlayer magnetic couplings (uncompensated antiferromagnets and compensated antiferromagnets, respectively).
- These magnetic differences lead to the observation of QAH and QSH states, with spin Hall conductivity tunable by layer number in even-layered structures.
Conclusions:
- The study demonstrates that layer number is a critical parameter for controlling both magnetic and topological properties in 2D LiFeTe.
- The discovered odd-even-layer-dependent QAH and QSH effects provide a novel mechanism for regulating quantum states in topological insulators.
- LiFeTe serves as a promising platform for exploring and engineering quantum phenomena in low-dimensional materials.
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