Multiple Valley\nModulations in Noncollinear Antiferromagnets

Two-dimensional valleys and magnetism are rising areas\nwith intriguing\nproperties and practical uses in advanced information technology.\nBy coupling valleys to collinear magnetism, valley degeneracy is lifted\nin a large number of magnetic valley materials to exploit the valley\ndegree of freedom. Beyond collinear magnetism, new coupling modes\nbetween valley and magnetism are few but highly desirable. By tight-binding\ncalculations of a breathing Kagome lattice, we demonstrate a tunable\nvalley structure and valley-contrasting physical properties in noncollinear\nantiferromagnets. Distinct from collinear magnetism, noncollinear\nantiferromagnetic order enables valley splittings even without spin–orbit\ncoupling. Both the canting and azimuthal angles of magnetic moments\ncan be used as experimentally accessible knobs to tune valley splittings.\nOur first-principles calculations of the Fe<sub>3</sub>C<sub>6</sub>O<sub>6</sub>-silicene-Fe<sub>3</sub>C<sub>6</sub>O<sub>6</sub> heterostructure\nalso exhibit tunable valley splittings in noncollinear antiferromagnetism,\nagreeing with our tight-binding results. Our work paves avenues for\ndesigning novel magnetic valley materials and energy-efficient valleytronic\ndevices based on noncollinear magnetism.