Spin Hall effect in a spin-1 chiral semimetal,Physical Review Research

当前位置： X-MOL 学术 › Phys. Rev. Research › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Spin Hall effect in a spin-1 chiral semimetal
Physical Review Research ( IF 3.5 ) Pub Date : 2021-07-29 , DOI: 10.1103/physrevresearch.3.033101
Ke Tang _{1,

2} , Yong-Chang Lau _{3,

4} , Kenji Nawa _{1,

5} , Zhenchao Wen ₁ , Qingyi Xiang ₁ , Hiroaki Sukegawa ₁ , Takeshi Seki _{3,

4} , Yoshio Miura ₁ , Koki Takanashi _{3,

4,

6} , Seiji Mitani _{1,

2}

Affiliation

The spin-1 chiral semimetal is a state of quantum matter hosting unconventional chiral fermions that extend beyond the common Dirac and Weyl fermions. B20-type CoSi is a prototypal material that accommodates such an exotic quasiparticle. To date, the spin-transport properties in the spin-1 chiral semimetals have not been thoroughly explored. In this work, we fabricated B20-CoSi thin films on sapphire

c

-plane substrates by magnetron sputtering and studied the spin Hall effect (SHE) by combining experiments and first-principles calculations. The SHE of CoSi was investigated using CoSi/CoFeB/MgO heterostructures via spin Hall magnetoresistance and harmonic Hall measurements. First-principles calculations yield an intrinsic spin Hall conductivity (SHC) at the Fermi level that is consistent with the experiments and reveal its unique Fermi-energy dependence. Unlike the Dirac and Weyl fermion-mediated Hall conductivities that exhibit a peaklike structure centering around the topological node, SHC of B20-CoSi is odd and crosses zero at the node with two antisymmetric local extrema of opposite sign situated below and above in energy. Hybridization between Co

d

-Si

p

orbitals and spin-orbit coupling are essential for the SHC, despite the small (∼1%) weight of the Si

p

orbital near the Fermi level. This work expands the horizon of topological spintronics and highlights the importance of Fermi-level tuning in order to fully exploit the topology of spin-1 chiral fermions for spin-current generation.

中文翻译：

自旋 1 手性半金属中的自旋霍尔效应

自旋 1 手性半金属是一种量子物质状态，包含非常规手性费米子，超出了常见的狄拉克和外尔费米子。B 20 型 CoSi 是一种原型材料，可以容纳这种奇异的准粒子。迄今为止，spin-1 手性半金属的自旋输运特性尚未得到彻底探索。在这项工作中，我们在蓝宝石上制造了B 20-CoSi 薄膜

C

通过磁控溅射制备-平面衬底，并结合实验和第一性原理计算研究了自旋霍尔效应（SHE）。通过自旋霍尔磁阻和谐波霍尔测量，使用 CoSi/CoFeB/MgO 异质结构研究 CoSi 的 SHE。第一性原理计算得出费米能级的固有自旋霍尔电导率 (SHC)，这与实验一致，并揭示了其独特的费米能量依赖性。与表现出以拓扑节点为中心的峰状结构的 Dirac 和 Weyl 费米子介导的霍尔电导率不同，B 20-CoSi 的SHC是奇数，并在节点处与零交叉，具有位于能量下方和上方的两个符号相反的反对称局部极值。Co之间的杂交