Evolution of Weyl nodes in Ni-doped thallium niobate pyrochlore Tl2−xNixNb2O7

Hu, Yuefang; Yue, Changming; Yuan, Dingsheng; Gao, Jun; Huang, Zhigao; Fang, Zhong; Fang, Chen; Weng, Hongming; Zhang, Wei

doi:10.1007/s11433-022-1940-1

Cited by 7 publications

(5 citation statements)

References 43 publications

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“…Due to some characteristics of Dirac dispersion, there may be nontrivial topological properties in this system and similar compounds. [24] This band is mainly contributed by the 𝑑 𝑧 2 orbital of Fe, which proves that RbSm2Fe4As4O2 has stronger threedimensionality. At the same time, this extra Fermi surface appears at the 𝛤 point, which also shows that Sm can effectively enhance the coupling strength within Fe2As2 bilayers.…”

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confidence: 83%

Role of Lanthanide in the Electronic Properties of RbLn ₂Fe₄As₄O₂ (Ln = Sm and Ho) Superconductors

Huang,

Ye,

Liu

et al. 2023

Chinese Phys. Lett.

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We focus on the effect of the ionic radius of lanthanides and the number of electrons in 4f orbitals on the superconducting temperature in 12442-type iron-based superconductors RbLn$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ (Ln = lanthanide). In order to do that, we have studied the electronic properties of RbSm$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ and RbHo$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ with the largest difference in ionic radius and number of electrons in 4f orbital, and the largest difference in superconducting temperature by using first-principles calculations. We predict that the ground state of RbLn$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ is spin-density-wave-type in-plane striped antiferromagnet (SAFM), and the magnetic moment around each Fe atom is about 2 ${\mu }_{B}$. RbSm$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ has a great influence on the energy band near the $\Gamma$ point, and a Dirac-like dispersion energy band appears. This band is mainly contributed by the d$_{z^2}$ orbital of Fe, which proves that RbSm$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ has a stronger three-dimensionality. At the same time, this extra Fermi surface appears at the $\Gamma$ point, which also shows that Sm can effectively enhance the coupling strength within Fe$_{2}$As$_{2}$ bilayers. The charge density difference $\rho$(RbHo$_{2}$Fe$_{4}$As$_{4}$O$_{2}$)-$\rho$(RbSm$_{2}$Fe$_{4}$As$_{4}$O$_{2}$) also confirms it. This increases the internal coupling strength of the bilayer Fe$_{2}$As$_{2}$ layers, which in turn leads to a higher T$_{c}$ of RbSm$_{2}$Fe$_{4}$As$_{4}$O$_{2}$ than RbHo$_{2}$Fe$_{4}$As$_{4}$O$_{2}$. Determining the details of their electronic structure, which may be closely related to superconductivity, is crucial to understanding the underlying mechanism. Such microscopic studies will provide useful clues for our further study of other high-temperature superconductors.

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confidence: 83%

Role of Lanthanide in the Electronic Properties of RbLn ₂Fe₄As₄O₂ (Ln = Sm and Ho) Superconductors

Huang,

Ye,

Liu

et al. 2023

Chinese Phys. Lett.

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“…Temperature-dependent Nernst effect measurements on Mn 3 Ge have demonstrated that the position of Weyl points can be manipulated by changing the temperature [10]. Recent efforts have focused on controlling the Weyl nodes in various compounds through doping, external pressure, and other means [23][24][25][26][27][28][29][30][31]. However, the precise understanding of the role played by external factors in the dynamics of Weyl Fermions is still incomplete.…”

Section: Introductionmentioning

confidence: 99%

Weyl points and anomalous transport effects tuned by the Fe doping in Mn₃Ge Weyl semimetal

Rai,

Jana,

Perßon

et al. 2024

New J. Phys.

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The discovery of a significantly large anomalous Hall effect in the chiral antiferromagnetic system - Mn3Ge- indicates that the Weyl points are widely separated in phase space and positioned near the Fermi surface. Inorder to examine the effects of Fe substitution in Mn3Ge on the presence and location of the Weyl points, we synthesized (Mn1−αFeα)3Ge (α = 0 − 0.30) compounds. The anomalous Hall effect was observed in compounds up to α = 0.22, but only within the temperature range where the magnetic structure remains the same as the Mn3Ge. Additionally, positive longitudinal magnetoconductance and planar Hall effect were detected within the same temperature and doping range. These findings strongly suggest the existence of Weyl points in (Mn1−αFeα)3Ge (α = 0 − 0.22) compounds. Notably, as Fe doping increases, there is a significant reduction in the magnitude of anomalous Hall conductivity, planar Hall effect, and positive longitudinal magnetoconductance, indicating that the Weyl points move further away from the Fermi surface. Consequently, it can be concluded that suitable dopants in the parent Weyl semimetals have the potential to tune the properties of Weyl points and the resulting anomalous electrical transport effects.

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“…[11][12][13][14][15] Since the TI realized in two-dimensional (2D) HgTe/CdTe quantum well [16][17][18] and three-dimensional (3D) Bi2Se3 family, [19,20] a number of 2D and 3D TIs have been proposed, such as 2D Xenes, [21][22][23][24][25][26] and 3D half-Heusler compounds, [27] chalcopyrites, [28] 𝛽-Ag2Te, [29] ZrTe5, [30] and WTe2. [31] The TSMs mainly include the Dirac semimetals (DSMs), [32][33][34][35] Weyl semimetals (WSMs), [36][37][38][39][40][41][42] nodal line semimetals (NLSMs), [43][44][45] and so on. For DSMs and WSMs, the conduction bands (CBs) and valence bands (VBs) form the isolated nodal points.…”

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confidence: 99%

Nontrivial Topological Phases in Ternary Borides M₂XB₂ (M=W, Mo; X=Co, Ni)

Yuan 袁,

Yue 岳,

Hu 胡

et al. 2024

Chinese Phys. Lett.

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The nontrivial band topologies protected by certain symmetries have attracted significant interest in condensed matter physics. The discoveries of nontrivial topological phases in real materials provide a series of archetype materials to further explore the topological physics. Ternary borides M2XB2 (M = W, Mo; X = Co, Ni) have been widely investigated as the wear-resistant and high-hardness materials. In this work, based on first-principles calculations, we find the nontrivial topological properties in these materials. Taking W2NiB2 as an example, this material shows the nodal line semimetal state in absence of spin-orbit coupling. Two types of nodal lines appear near the Fermi level simultaneously. One is protected by the combined space-inversion and time-reversal symmetry, and the other one is by the mirror symmetry. Part of these two types nodal lines form nodal chains. When spin-orbit coupling is included, these nodal lines are fully gapped and the system becomes a strong topological insulator with nontrivial Z2 index (1; 000). Our calculations demonstrate that a nontrivial spin-momentum locked surface Dirac cone appears on the ($\overline 1$10) surface. We also find that other isostructural ternary borides Mo2NiB2, Mo2CoB2 and W2CoB2 possess similar topological band structures. Therefore, our work not only enriches the understanding of band topology for ternary borides, but also lays the foundation for the further study of topological phases manipulation and potential spintronic applications in realistic materials.

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Evolution of Weyl nodes in Ni-doped thallium niobate pyrochlore Tl2−xNixNb2O7

Cited by 7 publications

References 43 publications

Role of Lanthanide in the Electronic Properties of RbLn ₂Fe₄As₄O₂ (Ln = Sm and Ho) Superconductors

Role of Lanthanide in the Electronic Properties of RbLn ₂Fe₄As₄O₂ (Ln = Sm and Ho) Superconductors

Weyl points and anomalous transport effects tuned by the Fe doping in Mn₃Ge Weyl semimetal

Nontrivial Topological Phases in Ternary Borides M₂XB₂ (M=W, Mo; X=Co, Ni)

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Evolution of Weyl nodes in Ni-doped thallium niobate pyrochlore Tl2−xNixNb2O7

Cited by 7 publications

References 43 publications

Role of Lanthanide in the Electronic Properties of RbLn 2Fe4As4O2 (Ln = Sm and Ho) Superconductors

Role of Lanthanide in the Electronic Properties of RbLn 2Fe4As4O2 (Ln = Sm and Ho) Superconductors

Weyl points and anomalous transport effects tuned by the Fe doping in Mn3Ge Weyl semimetal

Nontrivial Topological Phases in Ternary Borides M2XB2 (M=W, Mo; X=Co, Ni)

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Role of Lanthanide in the Electronic Properties of RbLn ₂Fe₄As₄O₂ (Ln = Sm and Ho) Superconductors

Role of Lanthanide in the Electronic Properties of RbLn ₂Fe₄As₄O₂ (Ln = Sm and Ho) Superconductors

Weyl points and anomalous transport effects tuned by the Fe doping in Mn₃Ge Weyl semimetal

Nontrivial Topological Phases in Ternary Borides M₂XB₂ (M=W, Mo; X=Co, Ni)