Domain wall induced spin-polarized flat bands in antiferromagnetic topological insulators

Petrov, Evgeniy K.; Men’shov, V. N.; Rusinov, Igor P.; Hoffmann, Martin; Ernst, A.; Otrokov, M. M.; Dugaev, V. K.; Menshchikova, Tatiana V.; Chulkov, Evgueni V.

doi:10.1103/physrevb.103.235142

Cited by 29 publications

(13 citation statements)

References 80 publications

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“…A recent study also predicts that the C = 3 state is achievable in the twisted MnBi 2 Te 4 bilayer . Finally, the MnBi 2 Te 4 -derived family of compounds , has been recently proposed as a magnetically tunable platform for realizing various symmetry-protected higher-order typologies, − hinged quantum spin Hall effect, and helical Chern insulator, as well as spin-polarized flat bands …”

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confidence: 99%

Topological Magnetic Materials of the (MnSb₂Te₄)·(Sb₂Te₃)_nvan der Waals Compounds Family

Eremeev

Rusinov

Koroteev

et al. 2021

J. Phys. Chem. Lett.

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Using density functional theory, we propose the (MnSb2Te4)·(Sb2Te3) n family of stoichiometric van der Waals compounds that harbor multiple topologically nontrivial magnetic phases. In the ground state, the first three members of the family (n = 0, 1, 2) are 3D antiferromagnetic topological insulators, while for n ≥ 3 a special phase is formed, in which a nontrivial topological order coexists with a partial magnetic disorder in the system of the decoupled 2D ferromagnets, whose magnetizations point randomly along the third direction. Furthermore, due to a weak interlayer exchange coupling, these materials can be field-driven into the FM Weyl semimetal (n = 0) or FM axion insulator states (n ≥ 1). Finally, in two dimensions, we reveal these systems to show intrinsic quantum anomalous Hall and AFM axion insulator states, as well as quantum Hall state, achieved under external magnetic field. Our results demonstrate that MnSb2Te4 is not topologically trivial as was previously believed that opens possibilities of realization of a wealth of topologically nontrivial states in the (MnSb2Te4)·(Sb2Te3) n family.

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confidence: 99%

Topological Magnetic Materials of the (MnSb₂Te₄)·(Sb₂Te₃)_nvan der Waals Compounds Family

Eremeev

Rusinov

Koroteev

et al. 2021

J. Phys. Chem. Lett.

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“…All the considered compounds were found to have an out-of-plane magnetization with practically absent in-plane MAE (see Table ). As can be seen from the Table , MAE is large and constitutes tenths of a millielectronvolt, which is far outside of the expected sub-millielectronvolt range found in similar Mn- or V-containing systems. , …”

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confidence: 70%

“…Recently, a family of V-containing planar AFM TIs was proposed. Their Néel temperatures were estimated to be up to 94 K (in contrast to the MnBi 2 Te 4 Néel temperature of 24.3 K , ). Other AFM TI materials containing Ti, Ni, and Eu were proposed as well .…”

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confidence: 89%

“…As can be seen from the Table 1, MAE is large and constitutes tenths of a millielectronvolt, which is far outside of the expected sub-millielectronvolt range found in similar Mn-or V-containing systems. 1,22 Now we address JT distortions and their impact on the properties of the compounds under study. In the above-discussed case we considered the R3̅ m phase consisting of septuple layer (SL) blocks, separated by a vdW gap.…”

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confidence: 99%

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Intrinsic Magnetic Topological Insulator State Induced by the Jahn–Teller Effect

Petrov

Ernst

Menshchikova

et al. 2021

J. Phys. Chem. Lett.

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The Jahn−Teller effect is a geometrical distortion which lowers the system symmetry and lifts orbital degeneracy in molecules and solids. It affects a wide range of properties, including magnetic and band structures. In this work we propose a family of Crcontaining intrinsic magnetic topological insulator materials which are subjected to a pseudo-Jahn−Teller effectCrBi 2 Se 4 , CrBi 2 Te 2 Se 2 , and CrBi 2 Te 4 . Using first-principles calculations we study their properties and investigate the impact of Jahn−Teller distortions on the electronic and magnetic properties. We show that these distortions can significantly affect magnetic anisotropy energy and band structure. Without the distortions accounted for, all three of the compounds exhibit a semimetallic band structure. The distortions open a band gap, which in the cases of CrBi 2 Te 2 Se 2 and CrBi 2 Te 4 is inverted. We also investigate the CrBi 2 Te 2 Se 2 and CrBi 2 Te 4 surface band structure and demonstrate that the surface states have a topological origin.

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“…The Mn 3d-states were treated employing the GGA+U approach 81 within the Dudarev scheme 82 . The U eff = U − J value for the Mn 3d-states was chosen to be equal to 5.34 eV, as in previous works [2][3][4][5]7,8,23,[83][84][85] . STM/S simulations were performed using the Tersoff-Hamann approximation.…”

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confidence: 99%

Native point defects and their implications for the Dirac point gap at MnBi$_2$Te$_4$(0001)

Garnica¹,

Otrokov²,

Aguilar³

et al. 2021

Preprint

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The Dirac point gap at the surface of the antiferromagnetic topological insulator MnBi2Te4 is a highly debated issue. While the early photoemission measurements reported on large gaps in agreement with theoretical predictions, other experiments found vanishingly small splitting of the MnBi2Te4 Dirac cone. Here, we study the crystalline and electronic structure of MnBi2Te4(0001) using scanning tunneling microscopy/spectroscopy (STM/S), micro(µ)-laser angle resolved photoemission spectroscopy (ARPES), and density functional theory (DFT) calculations. Our topographic STM images clearly reveal features corresponding to point defects in the surface Te and subsurface Bi layers that we identify with the aid of STM simulations as BiTe antisites (Bi atoms at the Te sites) and MnBi substitutions (Mn atoms at the Bi sites), respectively. X-ray diffraction (XRD) experiments further evidence the presence of cation (Mn-Bi) intermixing. Altogether, this affects the distribution of the Mn atoms, which, inevitably, leads to a deviation of the MnBi2Te4 magnetic structure from that predicted for the ideal crystal structure. Our transport measurements suggest that the degree of this deviation varies from sample to sample. Consistently, the ARPES/STS experiments reveal that the Dirac point gap of the topological surface state is different for different samples/sample cleavages. Our DFT surface electronic structure calculations show that, due to the predominant localization of the topological surface state near the Bi layers, MnBi defects can cause a strong reduction of the MnBi2Te4 Dirac point gap, given the recently proved antiparallel alignment of the MnBi moments with respect to those of the Mn layer. Our results provide a key to puzzle out the MnBi2Te4 Dirac point gap mystery.

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Domain wall induced spin-polarized flat bands in antiferromagnetic topological insulators

Abstract: Note that the quantities in rows 1-3 and the exchange coupling parameters in rows 4 and 5 are calculated with two very different methods and codes. See Methods section for details. ** Calculated/experimental values.

Cited by 29 publications

References 80 publications

Topological Magnetic Materials of the (MnSb₂Te₄)·(Sb₂Te₃)_nvan der Waals Compounds Family

Topological Magnetic Materials of the (MnSb₂Te₄)·(Sb₂Te₃)_nvan der Waals Compounds Family

Intrinsic Magnetic Topological Insulator State Induced by the Jahn–Teller Effect

Native point defects and their implications for the Dirac point gap at MnBi$_2$Te$_4$(0001)

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Domain wall induced spin-polarized flat bands in antiferromagnetic topological insulators

Abstract: Note that the quantities in rows 1-3 and the exchange coupling parameters in rows 4 and 5 are calculated with two very different methods and codes. See Methods section for details. ** Calculated/experimental values.

Cited by 29 publications

References 80 publications

Topological Magnetic Materials of the (MnSb2Te4)·(Sb2Te3)nvan der Waals Compounds Family

Topological Magnetic Materials of the (MnSb2Te4)·(Sb2Te3)nvan der Waals Compounds Family

Intrinsic Magnetic Topological Insulator State Induced by the Jahn–Teller Effect

Native point defects and their implications for the Dirac point gap at MnBi$_2$Te$_4$(0001)

Contact Info

Product

Resources

About

Topological Magnetic Materials of the (MnSb₂Te₄)·(Sb₂Te₃)_nvan der Waals Compounds Family

Topological Magnetic Materials of the (MnSb₂Te₄)·(Sb₂Te₃)_nvan der Waals Compounds Family