“Magic” Orientation Angles to Suppress Spin-Driven Hall Currents in Anisotropic 2D Materials with an Ideal Skyrmion Gas

Abstract

The Hall effect depending on conduction electron spin projection becomes very different for anisotropic 2D crystals. In this case, the spin-dependent electron current is strongly determined by the orientation angle, θ, of the sample with respect to an applied electric field. The spin-up and -down components of the direct and Hall charge currents oscillate with the angle 2θ. The direct and Hall components of the current have the structure where there are the angle-independent part, oscillation amplitude, and phase shift. All three quantitates strongly depend on the electron spin projection, electron mass ratio, and skyrmion size. We find that there are “magic” orientation angles where the spin-up, spin-down, and total Hall currents vanish. There is a great interest in computations based on 2D materials with skyrmions. Such properties can be useful for computer logic operations based on skyrmions.

The theory of transport in helical spin-structure crystals

“…These bands are anisotropic resulting in the origin of the parallel and perpendicular components of the electric currents according to Eq. (19). Electron-acoustic phonon interaction has been chosen as a scattering mechanism.…”

“…As shown in Ref. 19 , the parallel and perpendicular to the electric field components of electric current for an anisotropic crystal can be expressed as follows:…”

“…In the case of the band anisotropy, it was proven in Ref. 19 that the current has a perpendicular component if the angle between z-axis and an electric field is nonzero (see Eq. ( 19)).…”

The theory of transport in helical spin-structure crystals

“…As soon as f 1 has been found, we have determined the parallel and perpendicular conductivities assuming the angle between the z-axis and the electric field to be θ. As shown in [21], the parallel and perpendicular to the electric field components of electric current for an anisotropic crystal can be expressed as follows:…”

“…The anisotropy of the bands is schematically depicted in figure 4. In the case of the band anisotropy, it was proven in [21] that the current has a perpendicular component if the angle between z-axis and an electric field is nonzero (see equation (19)).…”