Tengdin Phoebe, Gentry Christian, Blonsky Adam, Zusin Dmitriy, Gerrity Michael, Hellbrück Lukas, Hofherr Moritz, Shaw Justin, Kvashnin Yaroslav, Delczeg-Czirjak Erna K, Arora Monika, Nembach Hans, Silva Tom J, Mathias Stefan, Aeschlimann Martin, Kapteyn Henry C, Thonig Danny, Koumpouras Konstantinos, Eriksson Olle, Murnane Margaret M
Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA.
Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.
Sci Adv. 2020 Jan 17;6(3):eaaz1100. doi: 10.1126/sciadv.aaz1100. eCollection 2020 Jan.
Heusler compounds are exciting materials for future spintronics applications because they display a wide range of tunable electronic and magnetic interactions. Here, we use a femtosecond laser to directly transfer spin polarization from one element to another in a half-metallic Heusler material, CoMnGe. This spin transfer initiates as soon as light is incident on the material, demonstrating spatial transfer of angular momentum between neighboring atomic sites on time scales < 10 fs. Using ultrafast high harmonic pulses to simultaneously and independently probe the magnetic state of two elements during laser excitation, we find that the magnetization of Co is enhanced, while that of Mn rapidly quenches. Density functional theory calculations show that the optical excitation directly transfers spin from one magnetic sublattice to another through preferred spin-polarized excitation pathways. This direct manipulation of spins via light provides a path toward spintronic devices that can operate on few-femtosecond or faster time scales.
赫斯勒化合物是未来自旋电子学应用中令人兴奋的材料，因为它们展现出广泛的可调节电子和磁相互作用。在此，我们使用飞秒激光在半金属赫斯勒材料CoMnGe中直接将自旋极化从一种元素转移到另一种元素。这种自旋转移在光入射到材料上时即刻启动，证明了在时间尺度小于10飞秒的情况下，角动量在相邻原子位点之间的空间转移。利用超快高谐波脉冲在激光激发过程中同时且独立地探测两种元素的磁状态，我们发现Co的磁化增强，而Mn的磁化迅速猝灭。密度泛函理论计算表明，光激发通过优选的自旋极化激发路径直接将自旋从一个磁亚晶格转移到另一个磁亚晶格。这种通过光对自旋的直接操控为可在几飞秒或更快时间尺度上运行的自旋电子器件提供了一条途径。
