High-Chern-number and high-temperature quantum Hall effect without Landau levels

Ge, Jun‐Yi; Liu, Yanzhao; Zhang, Yingbo; Li, Hao; Luo, Tianchuang; Wu, Yang; Xu, Yong; Wang, Jian

doi:10.1093/nsr/nwaa089

Cited by 328 publications

(285 citation statements)

References 34 publications

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“…Above all, quantized transport properties have been observed in MnBi 2 Te 4 thin flakes exfoliated from MnBi 2 Te 4 single crystals by several groups above 1.5 K, higher than in usual magnetically doped TI samples [34][35][36] . In odd-SL thick flakes, Yuanbo Zhang and Xianhui Chen's group observed quantized plateaus of the Hall resistance, as well as diminishing longitudinal resistance, both in the AFM configuration around zero magnetic field and in the FM configuration at magnetic field of several Tesla 35 .…”

Section: Research Progress On Mnbi 2 Tementioning

confidence: 87%

“…Rapid and exciting experimental progress has been made in MnBi 2 Te 4 -family materials in the past years, constructing one of the hottest topics in condensed matter physics recently 8,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] . Single-crystal samples of MnBi 2 Te 4 -family materials have been successfully prepared by several groups [20][21][22][23][24][25][26][27] .…”

Section: Research Progress On Mnbi 2 Tementioning

confidence: 99%

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MnBi2Te4-family intrinsic magnetic topological materials

2020

npj Quantum Mater.

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MnBi2Te4 and its derivative compounds have received focused research interests recently for their inherent magnetic order and the rich, robust and tunable topological phases hosted in them. Here, I briefly introduce MnBi2Te4-family intrinsic magnetic topological materials—the electronic and magnetic properties, the topological phase diagrams and the research progress made on them in the past years. I try to present a simple picture to understand their rich electronic, magnetic and topological properties, and a concise guide to engineer them for intended topological phases and the quantum anomalous Hall effect at higher temperature.

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Section: Research Progress On Mnbi 2 Tementioning

confidence: 87%

Section: Research Progress On Mnbi 2 Tementioning

confidence: 99%

MnBi2Te4-family intrinsic magnetic topological materials

2020

npj Quantum Mater.

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“…The QAH effect has been proposed to appear in the heterostructures of topological insulator (TI) and magnetic insulator through the magnetic proximity effect across the interface [13][14][15][16][17] . Another recent advance is the successful synthesis of a class of intrinsic magnetic TI materials, including MnBi 2 Te 4 , MnBi 2 Se 4 , and MnSb 2 Te 4 18,19 , in which A-type antiferromagnetism and topologically nontrivial band structure coexist, leading to the successful observation of the QAH state [20][21][22] . The QAH effect has also been observed in twisted bilayer graphene 23,24 .…”

Section: Introductionmentioning

confidence: 99%

Quantum anomalous Hall effect in two-dimensional magnetic insulator heterojunctions

Pan¹,

Yu²,

Zhang³

et al. 2020

npj Comput Mater

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Recent years have witnessed tremendous success in the discovery of topological states of matter. Particularly, sophisticated theoretical methods in time-reversal-invariant topological phases have been developed, leading to the comprehensive search of crystal database and the prediction of thousands of topological materials. In contrast, the discovery of magnetic topological phases that break time reversal is still limited to several exemplary materials because the coexistence of magnetism and topological electronic band structure is rare in a single compound. To overcome this challenge, we propose an alternative approach to realize the quantum anomalous Hall (QAH) effect, a typical example of magnetic topological phase, via engineering two-dimensional (2D) magnetic van der Waals heterojunctions. Instead of a single magnetic topological material, we search for the combinations of two 2D (typically trivial) magnetic insulator compounds with specific band alignment so that they can together form a type-III broken-gap heterojunction with topologically non-trivial band structure. By combining the data-driven materials search, first-principles calculations, and the symmetry-based analytical models, we identify eight type-III broken-gap heterojunctions consisting of 2D ferromagnetic insulators in the MXY compound family as a set of candidates for the QAH effect. In particular, we directly calculate the topological invariant (Chern number) and chiral edge states in the MnNF/MnNCl heterojunction with ferromagnetic stacking. This work illustrates how data-driven material science can be combined with symmetry-based physical principles to guide the search for heterojunction-based quantum materials hosting the QAH effect and other exotic quantum states in general.

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“…Layered quantum materials, such as graphene and twodimensional (2D) semiconductors of transition metal dichalcogenides, have revolutionized many fields in condensed matter physics and materials science because of their exotic quantum properties 1 . A new member in this family is MnBi 2 Te 4 that is an intrinsic antiferromagnetic topological insulator (TI) currently under intensive study [2][3][4][5][6][7][8][9][10] . In MnBi 2 Te 4 , the interplay between magnetism and topology has been shown to generate exotic quantum states, including quantum anomalous Hall effect 4 , axion insulator 6,7 , and high-Chern-number insulator 9 , upon exfoliation to atomically thin layers.…”

Section: Introductionmentioning

confidence: 99%

Subtle metastability of the layered magnetic topological insulator MnBi2Te4 from weak interactions

et al. 2020

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Layered quantum materials can host interesting properties, including magnetic and topological, for which enormous computational predictions have been done. Their thermodynamic stability is much less visited computationally, which however determines the existence of materials and can be used to guide experimental synthesis. MnBi2Te4 is one of such layered quantum materials that was predicted to be an intrinsic antiferromagnetic topological insulator, and later experimentally realized but in a thermodynamically metastable state. Here, using a combined first-principles-based approach that considers lattice, charge, and spin degrees of freedom, we investigate the metastability of MnBi2Te4 by calculating the Helmholtz free energy for the reaction Bi2Te3 + MnTe → MnBi2Te4. We identify a temperature range (~500–873 K) in which the compound is stable with respect to the competing binary phases, consistent with experimental observation. We validate the predictions by comparing the calculated specific heats contributed from different degrees of freedom with experimental results. Our findings indicate that the degrees of freedom responsible for the van der Waals interaction, lattice vibration, magnetic coupling, and nontrivial band topology in MnBi2Te4 not only enable emergent phenomena but also play a crucial role in determining its thermodynamic stability. This conclusion lays the foundation for the future computational material synthesis of novel layered systems.

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High-Chern-number and high-temperature quantum Hall effect without Landau levels

Cited by 328 publications

References 34 publications

MnBi2Te4-family intrinsic magnetic topological materials

MnBi2Te4-family intrinsic magnetic topological materials

Quantum anomalous Hall effect in two-dimensional magnetic insulator heterojunctions

Subtle metastability of the layered magnetic topological insulator MnBi2Te4 from weak interactions

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