Space-Time Symmetry of Transport Coefficients

Kleiner, W. H.

doi:10.1103/physrev.142.318

Cited by 134 publications

(121 citation statements)

References 8 publications

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“…Thus, the corresponding SHE is anisotropic on the basis of the linear response. The existing symmetries in the material, such as TRS and mirror reflections, force many tensor elements to be zero or equivalent [35,36], leaving only three groups of nonzero elements, σ Table I shows the calculated SHC for four WSM compounds, TaAs, TaP, NbAs, and NbP, in which the Fermi energy lies at the electron-hole compensation (charge neutral) point and the temperature is zero K. From right to left, the amplitude of the SHC increases quickly for a given SHC element, which is consistent with the increasing trend of SOC for these four compounds [19,37]. For a given compound (except NbP), σ z xy is much larger than the corresponding σ y zx and σ x yz .…”

Section: Taas Tap Nbas Nbp σmentioning

confidence: 99%

Strong Intrinsic Spin Hall Effect in the TaAs Family of Weyl Semimetals

2016

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Since their discovery, topological insulators have been expected to be ideal spintronic materials owing to the spin currents carried by surface states with spin-momentum locking. However, the bulk doping problem remains an obstacle that hinders such application. In this work, we predict that a newly discovered family of topological materials, the Weyl semimetals, exhibits large intrinsic spin Hall effects that can be utilized to generate and detect spin currents. Our ab initio calculations reveal a large spin Hall conductivity that is comparable to that of 4d and 5d transition metals. The spin Hall effect originates intrinsically from the bulk band structure of Weyl semimetals, which exhibit a large Berry curvature and spin-orbit coupling, so the bulk carrier problem in the topological insulators is naturally avoided. Our work not only paves the way for employing Weyl semimetals in spintronics, but also proposes a new guideline for searching for the spin Hall effect in various topological materials.Topological insulators (TIs) are characterized by metallic surface states inside the bulk energy gap [1,2], in which the spin and momentum are locked together with a vortex-like spin texture. Because counterpropagating surface states carry opposite spins, if charge current is introduced into a nominally perfect TI (with no bulk conductivity), the current should be fully spinpolarized. Thus, TIs have been considered as excellent materials for generating spin current, and this expectation has stimulated several recent experimental studies of the spin Hall effect (SHE) in TIs such as Bi 2 Se 3 [3] and (Bi 0.5 Sb 0.5 ) 2 Te 3 [4] that demonstrated highly efficient spin current conversion. However, the unavoidable bulk carrier problem remains an obstacle to widespread application of TIs. Interestingly, an exotic type of topological semimetal, the Weyl semimetal (WSM), exhibits similar spin-momentum locking in both the bulk and topological surface states [5][6][7][8][9]. Therefore, we are motivated to study the SHE, which refers to transverse spin current generation by a longitudinal charge current and is essential for state-of-the-art spintronic applications [10], in this new family of topological materials.In a WSM, the conduction and valence bands cross each other linearly in the three-dimensional (3D) momentum space near the Fermi energy through nodal points, called Weyl points, in a 3D analog of the band structure of graphene. Because of strong spin-orbit coupling (SOC), the Weyl points act as sources or sinks of the Berry curvature [11], which characterizes the entanglement between the conduction and valence bands. Here, we naturally expect the existence of a large SHE intrinsically originating from the bulk band structure, because the SHE is derived from the spinmomentum locking and Berry curvature of the electronic bands [12,13]. Recently, the first family of WSMs was predicted [14,15] and discovered by angle-resolved photoemission spectroscopy [16][17][18][19] in the transition-metal * yan@cpfs.mpg.de TABLE I. Nonz...

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Section: Taas Tap Nbas Nbp σmentioning

confidence: 99%

Strong Intrinsic Spin Hall Effect in the TaAs Family of Weyl Semimetals

2016

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“…In order to calculate the XMCD properties one has to take into account both magnetism and SO coupling when dealing with the electronic structure of the material considered, since the symmetry reduction in comparison with the paramagnetic state, which causes XMCD effect and is due to magnetic ordering, has consequences only when SO coupling is considered in addition [26].…”

Section: Crystal Structure and Computational Detailsmentioning

confidence: 99%

Electronic structure and excited-state properties of Co_{2}TiSn and Co_{2}ZrSn from ab initio calculations

Bekenov¹,

Antonov²,

Shpak³

et al. 2005

Condens. Matter Phys.

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The electronic structure, magnetism as well as the excited-state properties such as the optical and x-ray magnetic circular dichroism (XMCD) spectra of the Heusler alloys Co 2 TiSn and Co 2 ZrSn were investigated theoretically from first principles using the fully relativistic Dirac LMTO band structure method. The origin of the XMCD spectra at the Co L 2,3 edges in the compounds is examined. Densities of valence states, orbital and spin magnetic moments as well as optical spectra are analyzed and discussed. The calculated results are compared with the available experimental data.

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“…Using straightforward symmetry considerations it can be shown that all MO phenomena are caused by the symmetry reduction -compared to the paramagnetic state -caused by magnetic ordering [23]. Concerning the optical properties this symmetry reduction only has consequences when spin-orbital (SO) coupling is considered in addition.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Electronic structure and magneto-optical Kerr effect in the compound UCuP2

Horpynyuk

Nemoshkalenko

Antonov

et al. 2002

Low Temperature Physics

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The optical and magneto-optical (MO) spectra of the ternary compound UCuP 2 are investigated from first principles, using the fully relativistic Dirac linear-muffin-tin-orbital band structure method and density-functional theory in the local spin-density approximation. Within a band-like description of the 5f electrons, good agreement with the measured MO spectra is obtained. The origin of the Kerr rotation in the compound is examined.

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Space-Time Symmetry of Transport Coefficients

Cited by 134 publications

References 8 publications

Strong Intrinsic Spin Hall Effect in the TaAs Family of Weyl Semimetals

Strong Intrinsic Spin Hall Effect in the TaAs Family of Weyl Semimetals

Electronic structure and excited-state properties of Co_{2}TiSn and Co_{2}ZrSn from ab initio calculations

Electronic structure and magneto-optical Kerr effect in the compound UCuP2

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