Spin–orbit torque switching using the spin Hall effect in heavy metals and topological insulators has a great potential for ultralow power magnetoresistive random-access memory. To be competitive with conventional spin-transfer torque switching, a pure spin current source with a large spin Hall angle (θ_SH > 1) and high electrical conductivity (σ > 10⁵ Ω⁻¹ m⁻¹) is required. Here we demonstrate such a pure spin current source: conductive topological insulator BiSb thin films with σ ≈ 2.5 × 10⁵ Ω⁻¹ m⁻¹, θ_SH ≈ 52 and spin Hall conductivity σ_SH ≈ 1.3 × 10⁷ \(\frac{\hbar }{{2e}}\)Ω⁻¹ m⁻¹ at room temperature. We show that BiSb thin films can generate a very large spin–orbit field of 2.3 kOe MA^–1 cm² and a critical switching current density as low as 1.5 MA cm^–2 in Bi_0.9Sb_0.1/MnGa bilayers, which underlines the potential of BiSb for industrial applications.

在重金属和拓扑绝缘体中使用自旋霍尔效应的自旋轨道转矩切换对于超低功率磁阻随机存取存储器具有巨大的潜力。为了与常规自旋转移矩开关，具有大的自旋霍尔角的纯自旋电流源（竞争θ _SH  > 1）和高导电性（σ  > 10 ⁵  Ω ^-1 米^-1）是必需的。在这里，我们证明这样的纯自旋电流源：导电拓扑绝缘体BISB薄膜与σ  ≈2.5×10 ⁵  Ω ^-1 米^-1，θ _SH  ≈52和自旋霍尔电导率σ_SH≈1.3  ×10 ⁷  \（\ frac {\ hbar} {{2e}} \） Ω ^-1  m ^-1在室温下。我们证明了BiSb薄膜可以在Bi _0.9 Sb _0.1 / MnGa双层中产生2.3 kOe MA ^–1  cm ²的非常大的自旋轨道场和临界开关电流密度低至1.5 MA cm ^–2。用于工业应用的BiSb。