Spin friction in two-dimensional antiferromagnetic crystals

The spin-state-dominated frictional force and stick-slip behaviors are shown through first-principles calculations using Mn2C, a two-dimensional antiferromagnetic crystal, as a prototype. While the frictional force in the spin-unpolarized state is isotropic and independent with forward and backward moving directions, the antiferromagnetic ordering not only reduces the rotational symmetries of potential energy surfaces, but also dramatically changes the shapes of energy landscapes on the energetically preferred sliding paths, leading to anisotropic and even direction-dependent frictional force. Besides, a novel stick-slip behavior with the slips occurring across a fractional number of lattice sites is observed and the transition conditions of the stick-slip behavior can be predicted by the Tomlinson model.