Effects of structure dimensionality and chemical identity on persistent spin textures

Persistent spin textures, materials with a unidirectional spin configuration in momentum space, show promise for spintronics applications owing to their theoretically infinite spin lifetimes. For noncentrosymmetric bulk materials, it has been shown that the PST can be enforced by the symmetry of the material [1]. Bulk ternary oxides that exhibit both symmetry-protected PSTs (type I) and ferroelectric polarizations are ideal as the spin-orientation may be switched by an electric field; however, few examples have been found. Group-IV monochalcogenide MX monolayers (M=Sn, Ge and X = S, Se, Te) also host both an in-plane ferroelectric polarization and a PST [2]. Through comparing these two groups of materials we discuss the effect material dimensionality, chemistry, and local coordination has on the effective spin-orbit coupling (SOC) parameters and what the implications are for the PST quality and the persistent helix mode. This discussion will be oriented around assessing PSTs feasibility for use in spintronic devices and clarify future directions for research in this field.

[1] X. Lu and J.M. Rondinelli. Discovery Principles and Materials for Symmetry-Protected Persistent Spin Textures with Long Spin Lifetimes. Matter 3, 1211 (2020).

[2] M.A Absor and F. Ishii. Intrinsic persistent spin helix state in two-dimensional group-IV monochalcogenide MX monolayers (M = Sn or Ge and X = S, Se, Te). Phys. Rev. B, 100, 115104 (2019).