Orbital angular momentum textures and currents in a discrete helix: Equilibrium and linear response

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Nonequilibrium orbital angular momentum (OAM) in low-dimensional systems is gaining attention.
• Chirality's role in generating OAM and spin polarization is under investigation.

Purpose of the Study:

• To introduce a minimal model for studying chirality-induced OAM.
• To investigate the generation of OAM and spin polarization in chiral systems without atomic spin-orbit coupling.

Main Methods:

• A minimal three-orbital tight-binding model for a single helical chain.
• Analysis of momentum-dependent orbital-angular-momentum texture via Slater-Koster hybridization.
• Inclusion of spin degrees of freedom to study orbital-to-spin transduction.

Main Results:

• Chirality alone generates a momentum-dependent OAM texture.
• Orbital texture leads to chirality-dependent end magnetization and orbital Edelstein response.
• Orbital texture acts as a source of spin polarization through orbital-to-spin transduction, driven by molecular orbital interactions.

Conclusions:

• Chirality is the minimal ingredient for OAM response in 1D systems.
• An orbital route to spin selectivity in chiral conductors is supported.
• Stronger spin response is achievable through molecular orbital interactions compared to atomic spin-orbit coupling.