Spin Transport Properties of Fractal and Non-Fractal Thinfilm

TL;DR

This study investigates how fractal structures influence spin transport properties in thin films, revealing that the spin Hall effect's behavior critically depends on the fractal geometry and shape of the material.

Contribution

It introduces a quantum transport model for spin behavior in fractal thin films, highlighting the impact of fractal geometry on spin transport phenomena.

Findings

Spin Hall effect distribution depends on fractal structure.

Spin density and transmission vary with film shape and dimension.

Fractal geometry significantly influences spin transport properties.

Abstract

Spatial behavior of spin transport in a Sierpinski gasket fractal is studied from two dimensions to quasi-one dimension subject to the Rashba spin-orbital coupling. With two normal metal leads represented by self-energy matrix, discretizing the derived continuous Hamiltonian to a tight-binding version, Landauer-Keldysh formalism for nonequilibrium transport can be applied. It was observed that the spin Hall effect presents in the distribution of spin density critically depends on the fractal structure and the shape of the thinfilm. The local spin density and transmission are numerically tested by the present quantum transport calculation for the fractal and non-fractal thinfilm varying from two-dimensional square-lattice into quasi-one dimensional fractal shape (Sierpinski triangles).