Extrinsic and intrinsic ratchet response of a quantum dissipative spin-orbit medium

TL;DR

This paper shows that in quantum dissipative systems with spin-orbit interactions, charge and spin ratchet effects arise intrinsically from the system's properties, not from external asymmetries, challenging traditional views.

Contribution

It demonstrates that intrinsic spin-orbit coupling and quantum dissipation alone can produce ratchet effects without extrinsic asymmetry.

Findings

Charge and spin ratchet currents occur due to intrinsic spin-orbit asymmetry.

Extrinsic spatial asymmetry is unnecessary for ratchet effects in these systems.

Quantum dissipation enhances the intrinsic ratchet response.

Abstract

Traditionally the charge ratchet effect is considered as a consequence of the extrinsic spatial asymmetry engineered by external asymmetric periodic potentials. Here we demonstrate that electrically and magnetically driven dissipative systems with spin-orbit interactions represent an exception from this standard idea. The charge and spin ratchet currents appear just due to the coexistence of quantum dissipation with the intrinsic spatial asymmetry of the spin-orbit coupling. The extrinsic spatial asymmetry is inessential.