Wang Fei, Shi Guoyi, Kim Kyoung-Whan, Park Hyeon-Jong, Jang Jae Gwang, Tan Hui Ru, Lin Ming, Liu Yakun, Kim Taeheon, Yang Dongsheng, Zhao Shishun, Lee Kyusup, Yang Shuhan, Soumyanarayanan Anjan, Lee Kyung-Jin, Yang Hyunsoo
Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, Singapore, Singapore.
Nat Mater. 2024 Jun;23(6):768-774. doi: 10.1038/s41563-023-01774-z. Epub 2024 Jan 19.
The key challenge of spin-orbit torque applications lies in exploring an excellent spin source capable of generating out-of-plane spins while exhibiting high spin Hall conductivity. Here we combine PtTe for high spin conductivity and WTe for low crystal symmetry to satisfy the above requirements. The PtTe/WTe bilayers exhibit a high in-plane spin Hall conductivity σ ≈ 2.32 × 10 × ħ/2e Ω m and out-of-plane spin Hall conductivity σ ≈ 0.25 × 10 × ħ/2e Ω m, where ħ is the reduced Planck's constant and e is the value of the elementary charge. The out-of-plane spins in PtTe/WTe bilayers enable the deterministic switching of perpendicular magnetization at room temperature without magnetic fields, and the power consumption is 67 times smaller than that of the Pt control case. The high out-of-plane spin Hall conductivity is attributed to the conversion from in-plane spin to out-of-plane spin, induced by the crystal asymmetry of WTe. Our work establishes a low-power perpendicular magnetization manipulation based on wafer-scale two-dimensional van der Waals heterostructures.
自旋轨道矩应用的关键挑战在于探索一种出色的自旋源，该自旋源能够产生面外自旋，同时展现出高自旋霍尔电导率。在此，我们将具有高自旋电导率的PtTe与低晶体对称性的WTe相结合，以满足上述要求。PtTe/WTe双层结构展现出高的面内自旋霍尔电导率σ≈2.32×10×ħ/2eΩ·m和面外自旋霍尔电导率σ≈0.25×10×ħ/2eΩ·m，其中ħ为约化普朗克常数，e为元电荷的值。PtTe/WTe双层结构中的面外自旋能够在室温下无磁场情况下实现垂直磁化的确定性翻转，且功耗比Pt控制情况小67倍。高面外自旋霍尔电导率归因于由WTe的晶体不对称性所诱导的面内自旋到面外自旋的转换。我们的工作基于晶圆级二维范德华异质结构建立了一种低功耗垂直磁化操控方法。
