Experimental Realization of an Intrinsic Magnetic Topological Insulator<sup>*</sup>

Gong, Yan; Guo, Jingwen; Zhang, Yingbo; Zhu, Kai; Liao, Menghan; Liu, Xiaozhi; Zhang, Qinghua; Gu, Lin; Tang, Lin; Feng, Xiao; Zhang, Ding; Li, Wei; Song, Can-Li; Wang, Lili; Yu, Pu; Chen, Xi; Wang, Yayu; Yao, Hong; Duan, Wenhui; Xu, Yong; Zhang, Shoucheng; Ma, Xu-Cun; Xue, Qi‐Kun; He, Ke

doi:10.1088/0256-307x/36/7/076801

Cited by 547 publications

(380 citation statements)

References 39 publications

Supporting

Mentioning

357

Contrasting

Unclassified

Order By: Relevance

“…1(d) shows the band dispersion along the white dashed line in panel (c), where two large and one shallow electron pocket can be easily identified. Surprisingly, a gapless Dirac state is clearly present, in stark contrast to the previous predictions and ARPES results [17,18,[23][24][25][26][27][28][29][30]. To elucidate the origin of this gapless Dirac state, we conducted DFT calculations on two types of magnetic moment configurations: A-type AFM and G-type AFM.…”

mentioning

confidence: 73%

Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4

et al. 2020

View full text Add to dashboard Cite

We use high-resolution, tunable angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations to study the electronic properties of single crystals of MnBi2Te4, a material that was predicted to be the first intrinsic antiferromagnetic (AFM) topological insulator. We observe both bulk and surface bands in the electronic spectra, in reasonable agreement with the DFT calculations results. In striking contrast to the earlier literatures showing a full gap opening between two surface band manifolds along (0001) direction, we observed a gapless Dirac cone remain protected in MnBi2Te4 across the AFM transition (TN = 24 K). Our data also reveal the existence of a second Dirac cone closer to the Fermi level, predicted by band structure calculations. Whereas the surface Dirac cones seem to be remarkably insensitive to the AFM ordering, we do observe splitting of the bulk band that develops below the TN . Having a moderately high ordering temperature, MnBi2Te4 provides a unique platform for studying the interplay between topology and magnetic ordering.

show abstract

mentioning

confidence: 73%

Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Conclusion -We have proposed MnBi 2n Te 3n+1 as a possible material class for realizing higher-order Möbius physics and various inversion-symmetric higher-order topological phases. For MnBi 2 Te 4 , MnBi 4 Te 7 , and MnBi 6 Te 10 , A-type AFM physics have been reported at zero field and signatures of canted AFM have been observed with an in-plane magnetic field [26,29,30,34,35,37]. Based on our topological index analysis, we expect those canted AFM systems to be exactly our proposed higher-order Möbius insulators, when the magnetic field is carefully aligned to preserve the glide symmetry.…”

mentioning

confidence: 98%

Möbius Insulator and Higher-Order Topology in MnBi2nTe3n+1

2020

View full text Add to dashboard Cite

We propose MnBi2nTe3n+1 as a magnetically tunable platform for realizing various symmetryprotected higher-order topology. Its canted antiferromagnetic phase can host exotic topological surface states with a Möbius twist that are protected by nonsymmorphic symmetry. Moreover, opposite surfaces hosting Möbius fermions are connected by one-dimensional chiral hinge modes, which offers the first material candidate of a higher-order topological Möbius insulator. We uncover a general mechanism to feasibly induce this exotic physics by applying a small in-plane magnetic field to the antiferromagnetic topological insulating phase of MnBi2nTe3n+1, as well as other proposed axion insulators. For other magnetic configurations, two classes of inversion-protected higher-order topological phases are ubiquitous in this system, which both manifest gapped surfaces and gapless chiral hinge modes. We systematically discuss their classification, microscopic mechanisms, and experimental signatures. Remarkably, the magnetic-field-induced transition between distinct chiral hinge mode configurations provides an effective "topological magnetic switch".

show abstract

“…The thinking and research on time-reversal symmetry in condensed matter systems directly led to the discovery of time-reversal-invariant Z2 TIs with the quantum spin Hall effect [4][5][6][7]. The introduction of magnetism into the Z2 TIs can produce more exotic topological quantum phenomena, such as the quantum anomalous Hall effect [8][9][10][11][12][13][14], axion insulator states [15][16][17][18][19][20][21] and chiral Majorana fermions [22].…”

mentioning

confidence: 99%

Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and
Li¹,
Gao²,
Duan³
et al. 2019
Phys. Rev. X
238
10
114
2
View full text Add to dashboard Cite

In magnetic topological insulators (TIs), the interplay between magnetic order and nontrivial topology can induce fascinating topological quantum phenomena, such as the quantum anomalous Hall effect, chiral Majorana fermions and axion electrodynamics. Recently, a great deal of attention has been focused on the intrinsic magnetic TIs, where disorder effects can be eliminated to a large extent, which is expected to facilitate the emergence of topological quantum phenomena. In despite of intensive efforts, the experimental evidence of topological surface states (SSs) remains elusive. Here, by combining first-principles calculations and angle-resolved photoemission spectroscopy (ARPES) experiments, we have revealed that EnSn2As2 is an antiferromagnetic TI with observation of Dirac SSs consistent with our prediction.We also observed gapless Dirac SSs in another antiferromagnetic TI MnBi2Te4, which were missed in previous ARPES study. These results provide clear evidence for nontrivial topology of the two intrinsic magnetic TIs. Moreover, the topological SSs show no observable changes across the magnetic transitions within the experimental resolution, indicating that the magnetic order has limited effect on the topological SSs, which can be attributed to weak hybridization between the magnetic states and the topological electronic states. This provides insights for further studies that the correlations between magnetism and topological states need to be strengthened to induce larger gaps of the topological SSs, which will facilitate the realization of topological quantum phenomena at higher temperatures.

show abstract

Experimental Realization of an Intrinsic Magnetic Topological Insulator^*

Cited by 547 publications

References 39 publications

Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4

Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4

Möbius Insulator and Higher-Order Topology in MnBi2nTe3n+1

Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and
Li¹,
Gao²,
Duan³
et al. 2019
Phys. Rev. X
238
10
114
2
View full text Add to dashboard Cite

Contact Info

Product

Resources

About

Experimental Realization of an Intrinsic Magnetic Topological Insulator*

Cited by 547 publications

References 39 publications

Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4

Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4

Möbius Insulator and Higher-Order Topology in MnBi2nTe3n+1

Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and Li1, Gao2, Duan3 et al. 2019Phys. Rev. X238101142View full textAdd to dashboardCite

Contact Info

Product

Resources

About

Experimental Realization of an Intrinsic Magnetic Topological Insulator^*

Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and
Li¹,
Gao²,
Duan³
et al. 2019
Phys. Rev. X
238
10
114
2
View full text Add to dashboard Cite