In-plane antiferromagnetic moments and magnetic polaron in the axion topological insulator candidate 
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Zhang, Yang; Deng, Ke; Zhang, Xiao; Wang, Meng; Wang, Yuan; Liu, Cai; Mei, Jia-Wei; Kumar, Shiv; Schwier, Eike F.; Shimada, Kenya; Chen, Chao‐Yu; Shen, Bing

doi:10.1103/physrevb.101.205126

Cited by 58 publications

(40 citation statements)

References 34 publications

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“…Finally, a true AXI state only occurs for insulating compounds, but resistance and angle-resolved-electron-photoemission data for EuIn 2 As 2 are consistent with it being a slightly hole-doped compensated semimetal 17 , 23 , see Supplementary Fig. 10 c. Thus, E F needs to be shifted into the bulk gap for an AXI to be observed.…”

Section: Discussionmentioning

confidence: 76%

“…1 c 15 , 16 . The magnetic Eu 2+ (spin ) layers undergo antiferromagnetic (AF) ordering at a Néel temperature of T N ≈ 18 K 17 which density functional theory (DFT) calculations predict to be A-type 18 . A-type order is collinear, with the ordered Eu magnetic moments μ ferromagnetically aligning in each layer and the layers stacking AF along c .…”

Section: Introductionmentioning

confidence: 99%

“…The magnetic Eu 2+ (spin S ¼ 7 2 ) layers undergo antiferromagnetic (AF) ordering at a Néel temperature of T N ≈ 18 K 17 which density functional theory (DFT) calculations predict to be A-type 18 . A-type order is collinear, with the ordered Eu magnetic moments μ ferromagnetically aligning in each layer and the layers stacking AF along c. Theory predicts that depending on the orientation of μ, the A-type order leads to an AXI that is either a TCI with some gapless surfaces or a higher-order topological insulator with chiral-hinge states 17,18 . Attractively, the ordered Eu moments may influence topological fermions in In 2 As 2 layers, providing a path for in situ control of band topology.…”

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confidence: 99%

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Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

et al. 2021

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Knowledge of magnetic symmetry is vital for exploiting nontrivial surface states of magnetic topological materials. EuIn2As2 is an excellent example, as it is predicted to have collinear antiferromagnetic order where the magnetic moment direction determines either a topological-crystalline-insulator phase supporting axion electrodynamics or a higher-order-topological-insulator phase with chiral hinge states. Here, we use neutron diffraction, symmetry analysis, and density functional theory results to demonstrate that EuIn2As2 actually exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180∘ rotation and time-reversal symmetries: $${C}_{2}\times {\mathcal{T}}={2}^{\prime}$$ C 2 × T = 2 ′ . Surfaces protected by $${2}^{\prime}$$ 2 ′ are expected to have an exotic gapless Dirac cone which is unpinned to specific crystal momenta. All other surfaces have gapped Dirac cones and exhibit half-integer quantum anomalous Hall conductivity. We predict that the direction of a modest applied magnetic field of μ0H ≈ 1 to 2 T can tune between gapless and gapped surface states.

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Section: Discussionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

et al. 2021

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“…A topological crystalline insulator phase with gapless surface states on the (100), (010), and (001) surfaces is expected for in-plane oriented magnetic moments, whereas a higherorder topological insulator phase with chiral hinge states is predicted if the magnetic moments are out-of-plane oriented [42]. From an experimental perspective, angle resolved photoemission spectroscopy (ARPES) studies have confirmed that EuIn 2 As 2 has hole-type Fermi pockets around the bulk Brillouin zone center [44][45][46], together with a heavily hole-doped surface state and an inversion of the bulk band in the AFM state [46] that is consistent with the theoretical prediction [42]. A negative magneto-resistance seen in magneto-transport measurements has provided evidence for a rather strong spin scattering of the carriers by the localized magnetic moments [43,44] that may affect the above described topological states.…”

Section: Introductionmentioning

confidence: 97%

“…194) space group, with alternating stacking of Eu 2+ and [In 2 As 2 ] 2− layers along the c-axis [42]. The Eu spins exhibit an A-type antiferromagnetic order below T N ≃ 18 K where they are parallel oriented within each layer and an antiparallel between neighbouring layers (along the c-axis) [43,44]. It has been predicted that the AFM order in EuIn 2 As 2 gives rise to an axion insulator with non-trivial topological states that are strongly influenced by the orientation of the magnetic moments.…”

Section: Introductionmentioning

confidence: 99%

Infrared study of the interplay of charge, spin, and lattice excitations in the magnetic topological insulator EuIn$_2$As$_{2}$

Xu,

Marsik,

Sarkar

et al. 2021

Preprint

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We report an infrared spectroscopy study of the axion topological insulator candidate EuIn2As2 for which the Eu moments exhibit an A-type antiferromagnetic (AFM) order below TN ≃ 18 K. The low energy response is composed of a weak Drude peak at the origin, a pronounced infraredactive phonon mode at 185 cm −1 and a free carrier plasma edge around 600 cm −1 . The interband transitions start above 800 cm −1 and give rise to a series of weak absorption bands at 5 000 and 12 000 cm −1 and strong ones at 20 000, 27 500 and 32 000 cm −1 . The AFM transition gives rise to pronounced anomalies of the charge response in terms of a cusp-like maximum of the free carrier scattering rate around TN and large magnetic splittings of the interband transitions at 5 000 and 12 000 cm −1 . The phonon mode at 185 cm −1 has also an anomalous temperature dependence around TN which suggests that it couples to the fluctuations of the Eu spins. The combined data provide evidence for a strong interaction amongst the charge, spin and lattice degrees of freedom.

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Controlling Spin Orientation and Metamagnetic Transitions in Anisotropic van der Waals Antiferromagnet CrPS₄ by Hydrostatic Pressure

Peng

Lin

Тиан

et al. 2021

Adv Funct Materials

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Controlling the phases of matter is a central task in condensed matter physics and materials science. In 2D magnets, manipulating spin orientation is of great significance in the context of the Mermin-Wagner theorem. Herein, a systematic study of temperature-and pressure-dependent magnetic properties up to 1 GPa in van der Waals CrPS 4 is reported. Owing to the temperature-dependent change of the magnetic anisotropy energy, the material undergoes a first-order spin reorientation transition with magnetic moments realigning from being almost parallel with the c axis in the ac plane to the quasi-1D chains of CrS 6 octahedra along the b axis upon heating. The spin reorientation temperature is suppressed after applying pressure, shifting the high-temperature phase to lower temperatures with the emergence of spinflop transitions under magnetic fields applied along the b axis. The saturation field increases with pressure, indicating the enhancement of interlayer antiferromagnetic coupling. However, the Néel temperature is slightly reduced, which is ascribed to the suppression of intralayer ferromagnetic coupling. The work demonstrates the control of spin orientation and metamagnetic transitions in layered antiferromagnets, which may provide new perspectives for exploring 2D magnetism and related spintronic devices.

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In-plane antiferromagnetic moments and magnetic polaron in the axion topological insulator candidate EuIn2As2

Cited by 58 publications

References 34 publications

Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

Infrared study of the interplay of charge, spin, and lattice excitations in the magnetic topological insulator EuIn$_2$As$_{2}$

Controlling Spin Orientation and Metamagnetic Transitions in Anisotropic van der Waals Antiferromagnet CrPS₄ by Hydrostatic Pressure

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In-plane antiferromagnetic moments and magnetic polaron in the axion topological insulator candidate EuIn2As2

Cited by 58 publications

References 34 publications

Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

Infrared study of the interplay of charge, spin, and lattice excitations in the magnetic topological insulator EuIn$_2$As$_{2}$

Controlling Spin Orientation and Metamagnetic Transitions in Anisotropic van der Waals Antiferromagnet CrPS4 by Hydrostatic Pressure

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Product

Resources

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Controlling Spin Orientation and Metamagnetic Transitions in Anisotropic van der Waals Antiferromagnet CrPS₄ by Hydrostatic Pressure