CoX2Y4: A Household of Two-Dimensional Magnets with Versatile Magnetic Order

Two-dimensional (2D) magnetic supplies supply a promising platform for nanoscale spintronics and for exploration of novel bodily phenomena. Right here, we predict a various vary of magnetic orders in cobalt-based 2D single septuple layers CoX₂Y₄, particularly, CoBi₂Te₄, CoBi₂Se₂Te₂, CoBi₂Se₄, and CoSb₂Te₄. Notably, CoBi₂Te₄ presents intrinsic non-collinear antiferromagnetism (AFM), whereas the others show collinear AFM. The emergence of AFM in all CoX₂Y₄ supplies is attributed to the antiferromagnetic 90° Co-Te(Se)-Co superexchange coupling. The origin of non-collinear/collinear orders lies in competing Heisenberg change interactions throughout the Co triangular lattice. A pivotal issue governing the non-collinear order of CoBi₂Te₄ is the vanishingly small ratio of change coupling between next-nearest neighbour Co and the closest neighbour Co (J₂/J₁ ~ 0.01). Moreover, our investigation into pressure results on CoX₂Y₄ lattices demonstrates the tunability of the magnetic state of CoSb₂Te₄ from collinear to non-collinear. Our prediction of the distinctive non-collinear AFM in 2D suggests the potential for observing extraordinary magnetic phenomena in 2D, together with non-collinear scattering and magnetic area partitions.