Tunneling current-controlled spin states in few-layer van der Waals magnets

The phenomenon of spin-transfer torque in bilayer metallic ferromagnets is well understood in terms of Landau-Lifshitz equation modified by magnetic torques carried by electric currents. However, when each ferromagnet layer is replaced by a single atomic layer of vdW magnetic insulators and electric transport through the bilayer is highly coherent, is the above picture still applicable? In a recent collaborative work [1], we argued that switching between layer-resolved collinear antiferromagnetic and ferromagnetic states in bilayer insulating CrI3 is achieved by tunneling-current-induced spin accumulation of opposite signs at metallic electrodes in contact with the respective CrI3 monolayers, which from a symmetry point of view is a general mechanism for switching between uniform and nonuniform magnetic states. A pedagogical news article summarizing the main findings of the work can be found here.

[1] ZhuangEn Fu, Piumi I. Samarawickrama, John Ackerman, Yanglin Zhu, Zhiqiang Mao, Kenji Watanabe, Takashi Taniguchi, Wenyong Wang, Yuri Dahnovsky, Mingzhong Wu, TeYu Chien, Jinke Tang, Allan H. MacDonald, Hua Chen* & Jifa Tian*, “Tunneling current-controlled spin states in few-layer van der Waals magnets”, Nature Communications 15, 3630 (2024).