Persistent spin texture enforced by symmetry

TL;DR

This paper predicts that certain non-centrosymmetric bulk materials inherently maintain a persistent spin texture due to symmetry constraints, potentially enhancing spintronics applications without the need for fine-tuning spin-orbit coupling parameters.

Contribution

It introduces a new class of materials where persistent spin texture is symmetry-enforced, expanding the possibilities for spintronics beyond quantum-well structures.

Findings

Density functional theory confirms PST in candidate materials.

BiInO3 exhibits PST around conduction band minimum.

Symmetry constraints stabilize spin texture independently of momentum.

Abstract

Persistent spin texture (PST) is the property of some materials to maintain a uniform spin configuration in the momentum space. This property has been predicted to support an extraordinarily long spin lifetime of carriers promising for spintronics applications. The PST is known to emerge when the strengths of two dominant spin-orbit couplings, the Rashba and linear Dresselhaus, are equal. This condition, however, is not trivial to achieve and requires tuning the Rashba and Dresselhaus parameters, as has been demonstrated with semiconductor quantum-well structures. Here we predict that there exist a class of non-centrosymmetric bulk materials where the PST is enforced by the non-symmorphic space group symmetry of the crystal. Around certain high symmetry points in the Brillouin zone, the sublattice degrees of freedom impose a constraint on the effective spin-orbit field, which remains independent of the momentum orientation and thus maintains the PST. We illustrate this behavior using density-functional theory calculations for a handful of promising candidates accessible experimentally. Among them is the ferroelectric oxide BiInO3-a wide band gap semiconductor which sustains a PST around the conduction band minimum. Our results broaden the range of materials, which can be employed in spintronics.