Perspectives of spin-textured ferroelectrics

Abstract

Spin–orbit coupling (SOC) links the spin degree of freedom to the orbital motion of electrons in a solid and plays an important role in the emergence of new physical phenomena. In non-centrosymmetric materials, the SOC locks the electron’s spin direction to its momentum resulting in non-trivial spin textures in the reciprocal space. Depending on the crystal symmetry, the spin texture may exhibit Rashba, Dresselhaus, persistent, or more intricate configurations. In ferroelectric materials these spin textures are coupled to the ferroelectric polarization and thus can be controlled by its orientation and magnitude. This provides a promising platform to explore the coupling between spin, orbital, valley, and lattice degrees of freedoms in solids and opens a new direction for nonvolatile spintronic devices, such as a spin-field-effect transistor and a valley spin valve. Here, we review the recent advances in spin-texture physics of ferroelectric materials and outline possible device implications.

Spin-neutral currents for spintronics

“…Another possibility is to utilize non-centrosymmetric insulators as a tunneling barrier layer in an AFMTJ. Due to the broken space inversion symmetry and spin-orbit coupling, the evanescent states in these insulators are spin-polarized 44 , 45 . Therefore, the Néel vector of the free antiferromagnetic layer can be used to control the matching between the propagating Bloch states in the antiferromagnetic electrode and the evanescent gap states in the barrier resulting in a TAMR effect.…”

“…Therefore, the Néel vector of the free antiferromagnetic layer can be used to control the matching between the propagating Bloch states in the antiferromagnetic electrode and the evanescent gap states in the barrier resulting in a TAMR effect. An additional useful functionality of this kind of tunnel junctions may be provided by a switchable polarization of the non-centrosymmetric insulating barrier layer if it is ferroelectric 45 .…”

Rashba spin splitting and anomalous spin textures in the bulk ferroelectric oxide perovskite KIO3

“…Ω Ω Ω(k) depends on the spatial symmetry of the system. For simplest case, C 2v point group symmetry, Ω Ω Ω(k) can be written as vector sum of linear Rashba 31 . Here, α R and α D are the Rashba and Dresselhaus coefficients, respectively.…”

Rashba dominated spin-splitting in the bulk ferroelectric oxide perovskite KIO3

“…Ω(k ) depends on the spatial symmetry of the system. For simplest case, C 2v point group symmetry, Ω(k ) can be written as vector sum of linear Rashba (Ω R = α R (k y , −k x , 0)) and Dresselhaus (Ω D = α D (k y , k x , 0)) spin-orbit fields [23]. Here, α R and α D are the Rashba and Dresselhaus coefficients, respectively.…”