Interfacial chirality-induced magnetic-field-free switching with high energy efficiency in all-vdW heterostructures.

Abstract

Chirality, a central concept across many scientific disciplines, continues to inspire the discovery of novel physical phenomena. In condensed matter physics, structural chirality-defined by the absence of mirror plane symmetries-has primarily been explored in bulk materials. However, new chiral phenomena can emerge uniquely at the interface, distinct from their bulk counterparts, when a chiral material forms a heterostructure. Here, we demonstrate that all van-der-Waals (vdW) heterostructure composed of the chiral Co_1/3TaS₂ and the achiral vdW ferromagnet Fe₃GeTe₂ exhibits two distinct and unconventional spin-orbit torques originating from the interfacial chirality. These torques enable magnetic-field-free switching of perpendicular magnetization with ultralow current density <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>~</mo><mspace></mspace><msup><mrow><mn>10</mn></mrow><mrow><mn>6</mn></mrow></msup><mspace></mspace><msup><mrow><mi>A</mi><mo>/</mo><mi>cm</mi></mrow><mrow><mn>2</mn></mrow></msup></math> and minimal power dissipation <math xmlns="http://www.w3.org/1998/Math/MathML"><mo><</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>15</mn></mrow></msup><mspace></mspace><msup><mrow><mi>W</mi><mo>/</mo><mi>m</mi></mrow><mrow><mn>3</mn></mrow></msup></math>. Moreover, by replacing Fe₃GeTe₂ with a similar vdW ferromagnet, Fe₃GaTe_2, but of higher Curie temperature, we achieved the magnetic-field-free switching at room temperature in the Fe₃GaTe₂/Co_1/3TaS₂ vdW heterostructure. Our findings establish interfacial chirality as a powerful new handle for spintronic control, opening a new pathway to explore chirality-induced phenomena beyond the bulk symmetry constraints - and paving the way toward highly efficient, low-power spintronic devices based on all-vdW heterostructures.