Progress and prospects in magnetic topological materials

Abstract: Magnetic topological materials represent a class of compounds whose properties are strongly influenced by the topology of the electronic wavefunctions coupled with the magnetic spin configuration. Such materials can support chiral electronic channels of perfect conduction, and can be used for an array of applications from information storage and control to dissipationless spin and charge transport. Here, we review the theoretical and experimental progress achieved in the field of magnetic topological materials beginning with the theoretical prediction of the Quantum Anomalous Hall Effect without Landau levels, and leading to the recent discoveries of magnetic Weyl semimetals and antiferromagnetic topological insulators. We outline the recent theoretical progress that resulted in the tabulation, for the first time, of all magnetic symmetry group representations and topology. We describe several experiments realizing Chern insulators, Weyl and Dirac magnetic semimetals, and an array of axionic and higher-order topological phases of matter as well as survey future perspectives.

• The paper presents a comprehensive review of theoretical advancements and experimental realizations in magnetic topological materials, emphasizing breakthroughs like the Quantum Anomalous Hall Effect.
• The study details the synthesis and analysis of materials such as MnBi2Te4 and Co3Sn2S2, showcasing the transition from theoretical predictions to experimental breakthroughs.
• The research proposes high-throughput searches and addresses synthesis challenges, paving the way for future quantum computing and spintronic applications.

An Overview of Progress and Prospects in Magnetic Topological Materials

The paper "Progress and Prospects in Magnetic Topological Materials" authored by B. Andrei Bernevig, Claudia Felser, and Haim Beidenkopf, presents a comprehensive review of the theoretical and experimental progress in the field of magnetic topological materials. This class of materials is distinguished by the interaction of the magnetic spin configuration with the topology of the electronic wavefunctions, leading to unique properties with significant implications for information storage, spin, and charge transport.

Theoretical Foundations and Recent Advances

The paper explores the foundational principles of magnetic topological insulators (MTIs) and magnetic topological semimetals (MTSMs), emphasizing the challenges associated with theoretically predicting magnetic materials over non-magnetic ones due to their interactive complexity. The field gained momentum with the theoretical prediction of the Quantum Anomalous Hall Effect (QAHE) and its subsequent realization. Further progress includes the discovery of magnetic Weyl semimetals and antiferromagnetic topological insulators, contributing to a deeper understanding of these materials.

One notable theoretical advancement presented is the comprehensive tabulation of all magnetic symmetry group representations, facilitating the exploration of novel phases of matter. This progress has enabled the synthesis of materials like MnBi$_2$Te$_4$, an antiferromagnetic topological insulator, and Co$_3$Sn$_2$S$_2$, a magnetic Weyl semimetal. These materials have opened pathways to study axial and higher-order topological phases directly.

Experimental Realizations and Characteristic Features

Experimentally, considerable strides have been made in realizing Chern insulators and characterizing the band structures and transport phenomena in magnetic topological materials. The realization of QAHE in thin films of certain doped and undoped compounds emphasizes the role of intrinsic magnetic orders. The research provides insights into the physical mechanisms underlying these phenomena, such as the gapping of Dirac cones and the emergence of chiral modes.

The synthesis of intrinsic antiferromagnetic topological insulators, such as MnBi$_2$Te$_4$, exemplifies the transition from theoretical prediction to experimental realization. This material shows quantized Hall conductance in thin films, highlighting its potential as a model system for understanding topological phases in magnetic contexts.

Implications and Future Directions

The implications of this research are profound for both theoretical exploration and practical applications. The manipulation of topological states through magnetic interactions offers potential advancements in quantum computing, spintronics, and energy-efficient devices. The paper indicates a promising future direction in achieving high-temperature QAHE and exploring room-temperature topological phases.

The authors propose a systematic high-throughput search for materials with desirable magnetic and topological properties, aiming to discover more materials with high Curie temperatures and robust topological characteristics. Addressing challenges such as precise material synthesis, classification of magnetic fragile topological indices, and magneto-optical response predictions will further expand the boundaries of this research field.

Conclusion

In conclusion, the paper provides an in-depth analysis of the current state and future prospects of magnetic topological materials. The combination of theoretical progress and experimental achievements establishes a solid foundation for exploring complex topological phases. This body of work not only advances the fundamental understanding of quantum materials but also paves the way for groundbreaking applications in next-generation technologies.