Intrinsic planar Hall effect induced from the layer pseudospin

The planar Hall effect (PHE) is an intriguing orbital magnetoelectric effect of electrons in coplanar electric and magnetic fields. Most existing proposals require strong spin-orbit coupling and the response manifests in the symmetric part of the conductivity tensor, which does not contribute to a dissipationless Hall current. Here we propose a novel mechanism to realize an intrinsic PHE by utilizing the layer pseudospin that is unique to layered van der Waals materials. In a bilayer structure, the layer pseudospin and interlayer coupling endow electrons with an effective in-plane magnetic moment. A planar magnetic field can couple to the in-plane magnetic moment, thus affects the orbital motion of electrons. The intrinsic PHE conductivity has a geometric origin rooted in the Berry curvature. Symmetry analysis shows that such an intrinsic PHE is linear in the magnetic field in bilayers without rotational symmetry, which also complies with the antisymmetric and dissipationless property of a genuine Hall effect. We show sizeable intrinsic PHE in widely studied bilayer materials, including strained twisted bilayer graphene and homobilayer transition metal dichalcogenides. Strain tuning and bias control of the intrinsic PHE are also explored.