Giant intrinsic spin Hall effect in W
            <sub>3</sub>
            Ta and other A15 superconductors

Derunova, Elena; Sun, Yan; Felser, Claudia; Parkin, S. S. P.; Yan, Binghai; Ali, Mazhar N.

doi:10.1126/sciadv.aav8575

Cited by 71 publications

(49 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our predicted intrinsic spin Hall conductivity for α-W (-762 (Ω-cm) −1 ) is comparable to the value (-785 (Ω-cm) −1 ) predicted by Sui et al 6 from first principles. However, our predicted intrinsic SHC for pristine β-W (-1840 (Ω-cm) −1 ) is much closer to that of Derunova et al 47 (-1900 (Ω-cm) −1 ) than the SHC (-1255 (Ω-cm) −1 ) reported by Sui et al 6 . It is unclear why there is a difference in this case.…”

Section: E Total Spin Hall Conductivitysupporting

confidence: 82%

“…It is unclear why there is a difference in this case. Both previous works used a Kubo-Greenwood approach where the Bloch wave functions from plane-wave (VASP for Sui et al 6 ) or localized orbital calculations (FPLO for Derunova et al 47 ) were mapped onto a tight-binding atomic basis set. The β-W A15 crystal structure is a more open crystal structure than α-W crystal structure and this could make the mapping process to a localized basis set more challenging.…”

Section: E Total Spin Hall Conductivitymentioning

confidence: 99%

“…The magnitude of the Spin Hall conductivity as a function of tungsten film thickness is shown for a variety of experimental measurements 4,5,37,41,42,[50][51][52][53][54] and theoretical predictions 6,47 . The calculated bulk intrinsic SHC for pristine β-W is shown at the Fermi energy (red dashed line) and for maximum possible value with p-type doping (black dashed line).…”

Section: Figmentioning

confidence: 99%

See 2 more Smart Citations

Impact of impurities on the spin Hall conductivity in β -W

McHugh

Goh

Gradhand

et al. 2020

Phys. Rev. Materials

View full text Add to dashboard Cite

While the metastable β (A15) phase of tungsten has one of the largest spin Hall angles measured, the origin of this high spin Hall conductivity is still unclear. Since large concentrations of oxygen and nitrogen are often used to stabilize β tungsten, it is not obvious whether the high spin Hall conductivity is due to an intrinsic or extrinsic effect. In this work, we have examined the influence of O and N dopants on the spin Hall conductivity and spin Hall angle of β-W. Using multiple first principles approaches, we examine both the intrinsic and extrinsic (skew scattering) contributions to spin Hall conductivity. We find that intrinsic spin Hall conductivity calculations for pristine β-W are in excellent agreement with experiment. However, when the effect of high concentrations (11 at.%) of O or N interstitials on the electronic structures is taken into account, the predicted intrinsic spin Hall conductivity is significantly reduced. Skew scattering calculations for O and N interstitials in β-W indicate that extrinsic contributions have a limited impact on the total spin Hall conductivity. However, we find that the spin-flip scattering at O and N impurities can well explain the experimentally found spin-diffusion length within the range of 1-5 nm. To explain these findings, we propose that dopants (O and N) help to stabilize β-W grains during film deposition and afterwards segregate to the grain boundaries. This process leads to films of relatively pristine small β-W grains and grain boundaries with high concentrations of O or N scattering sites. This combination provides high spin Hall conductivity and large electrical resistance, leading to high spin Hall angles. This work shows that engineering grain boundary properties in other high spin Hall conductivity materials could provide an effective way to boost the spin Hall angle.

show abstract

Section: E Total Spin Hall Conductivitysupporting

confidence: 82%

Section: E Total Spin Hall Conductivitymentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Impact of impurities on the spin Hall conductivity in β -W

McHugh

Goh

Gradhand

et al. 2020

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…To improve the energy efficiency of SOT‐driven magnetization switching, considerable efforts have been made to enhance the charge‐spin conversion efficiency of HM [ 6–9 ] and reduce the shunting current in the FM. [ 10,11 ] Engineering the bilayer structure [ 9,12 ] or replacing HM by novel materials with larger charge‐spin conversion efficiency and higher conductivity [ 10,13,14 ] are possible avenues to realize higher SOT efficiency.…”

Section: Figurementioning

confidence: 99%

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe₂

et al. 2020

View full text Add to dashboard Cite

Spin-orbit torque (SOT) provides an ultrafast and energy-efficient means to switch magnetization, which is of fundamental and technical importance for spintronic devices. [1][2][3][4][5] A typical SOT device consists of heavy metal/ferromagnet (HM/FM) bilayer, where the HM (e.g., Pt, W, Ta, etc.) converts charge current into spin current mainly due to the spin Hall effect (SHE) and then exerts a torque on the adjacent FM enabling magnetization manipulation. To improve the energy efficiency of SOT-driven magnetization switching, considerable efforts have been made to enhance the charge-spin conversion efficiency of HM [6][7][8][9] and reduce the shunting current in the FM. [10,11] Engineering the bilayer structure [9,12] or replacing HM by novel materials with larger charge-spin conversion efficiency and higher conductivity [10,13,14] are possible avenues to realize higher SOT efficiency. Manipulation of magnetization by electric-current-induced spin-orbit torque (SOT) is of great importance for spintronic applications because of its merits in energy-efficient and high-speed operation. An ideal material for SOT applications should possess high charge-spin conversion efficiency and high electrical conductivity. Recently, transition metal dichalcogenides (TMDs) emerge as intriguing platforms for SOT study because of their controllability in spin-orbit coupling, conductivity, and energy band topology. Although TMDs show great potentials in SOT applications, the present study is restricted to the mechanically exfoliated samples with small sizes and relatively low conductivities.Here, a manufacturable recipe is developed to fabricate large-area thin films of PtTe 2 , a type-II Dirac semimetal, to study their capability of generating SOT. Large SOT efficiency together with high conductivity results in a giant spin Hall conductivity of PtTe 2 thin films, which is the largest value among the presently reported TMDs. It is further demonstrated that the SOT from PtTe 2 layer can switch a perpendicularly magnetized CoTb layer efficiently. This work paves the way for employing PtTe 2 -like TMDs for wafer-scale spintronic device applications.

show abstract

“…The remaining real-space matrix elements are evaluated in a similar manner, by inverting Eqs. (28) and (29) and then using Eq. (35).…”

Section: Spin-current Matrix Elementsmentioning

confidence: 99%

Computation of intrinsic spin Hall conductivities from first principles using maximally localized Wannier functions

2019

View full text Add to dashboard Cite

We present a method to compute the intrinsic spin Hall conductivity from first principles using an interpolation scheme based on maximally-localized Wannier functions. After obtaining the relevant matrix elements among the ab initio Bloch states calculated on a coarse k-point mesh, we Fourier transform them to find the corresponding matrix elements between Wannier states. We then perform an inverse Fourier transform to interpolate the velocity and spin-current matrix elements onto a dense k-point mesh, and use them to evaluate the spin Hall conductivity as a Brillouin-zone integral. This strategy has a much lower computational cost than a direct ab initio calculation, without sacrificing the accuracy. We demonstrate that the spin Hall conductivities of platinum and doped gallium arsenide, computed with our interpolation scheme as a function of the Fermi energy, are in good agreement with those obtained in previous first-principles studies. We also discuss certain approximations that can be made, in the spirit of the tight-binding method, to simplify the calculation of the velocity and spin-current matrix elements in the Wannier representation. arXiv:1906.07139v1 [cond-mat.mes-hall]

show abstract

Giant intrinsic spin Hall effect in W ₃ Ta and other A15 superconductors

Cited by 71 publications

References 51 publications

Impact of impurities on the spin Hall conductivity in β -W

Impact of impurities on the spin Hall conductivity in β -W

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe₂

Computation of intrinsic spin Hall conductivities from first principles using maximally localized Wannier functions

Contact Info

Product

Resources

About

Giant intrinsic spin Hall effect in W 3 Ta and other A15 superconductors

Cited by 71 publications

References 51 publications

Impact of impurities on the spin Hall conductivity in β -W

Impact of impurities on the spin Hall conductivity in β -W

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe2

Computation of intrinsic spin Hall conductivities from first principles using maximally localized Wannier functions

Contact Info

Product

Resources

About

Giant intrinsic spin Hall effect in W ₃ Ta and other A15 superconductors

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe₂