Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
Beijing National fLaboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China.
Phys Rev Lett. 2023 May 26;130(21):216701. doi: 10.1103/PhysRevLett.130.216701.
The relativistic spin Hall effect and inverse spin Hall effect enable the efficient generation and detection of spin current. Recently, a nonrelativistic altermagnetic spin splitting effect (ASSE) has been theoretically and experimentally reported to generate time-reversal-odd spin current with controllable spin polarization in antiferromagnet RuO_{2}. The inverse effect, electrical detection of spin current via ASSE, still remains elusive. Here we show the spin-to-charge conversion stemming from ASSE in RuO_{2} by the spin Seebeck effect measurements. Unconventionally, the spin Seebeck voltage can be detected even when the injected spin current is polarized along the directions of either the voltage channel or the thermal gradient, indicating the successful conversion of x- and z-spin polarizations into the charge current. The crystal axes-dependent conversion efficiency further demonstrates that the nontrivial spin-to-charge conversion in RuO_{2} is ascribed to ASSE, which is distinct from the magnetic or antiferromagnetic inverse spin Hall effects. Our finding not only advances the emerging research landscape of altermagnetism, but also provides a promising pathway for the spin detection.
相对论自旋霍尔效应和逆自旋霍尔效应能够有效地产生和检测自旋流。最近，理论和实验上都报道了一种非相对论反铁磁自旋分裂效应（ASSE），它可以在反铁磁 RuO_2 中产生具有可控自旋极化的时间反演奇的自旋流。然而，反效应，即通过 ASSE 进行自旋流的电检测，仍然难以实现。在这里，我们通过自旋塞贝克效应测量展示了 RuO_2 中源自 ASSE 的自旋到电荷的转换。不同寻常的是，即使注入的自旋电流沿电压通道或热梯度的方向极化，也可以检测到自旋塞贝克电压，这表明 x 轴和 z 轴的自旋极化成功地转换为电荷电流。晶体轴依赖性的转换效率进一步证明了 RuO_2 中自旋到电荷的非平凡转换归因于 ASSE，这与磁性或反铁磁逆自旋霍尔效应不同。我们的发现不仅推进了反铁磁性这一新兴研究领域的发展，而且为自旋检测提供了一条有前途的途径。
