Towards colloidal spintronics through Rashba spin-orbit interaction in lead sulphide nanosheets

TL;DR

This paper demonstrates the potential for colloidal lead sulphide nanosheets to exhibit tunable Rashba spin-orbit interaction, enabling spintronic functionalities through electrical control and quantum confinement effects.

Contribution

It provides experimental evidence and theoretical analysis of Rashba spin-orbit interaction in colloidal lead sulphide nanosheets, a novel approach for spintronics using colloidal nanomaterials.

Findings

Rashba spin splitting observed in colloidal lead sulphide nanosheets.

Electrical tuning of spin-orbit interaction via gate electric field.

Quantum confinement influences Rashba effect in nanosheets.

Abstract

Employing the spin degree of freedom of charge carriers offers the possibility to extend the functionality of conventional electronic devices, while colloidal chemistry can be used to synthesize inexpensive and tuneable nanomaterials. In order to benefit from both concepts, Rashba spin-orbit interaction has been investigated in colloidal lead sulphide nanosheets by electrical measurements on the circular photo-galvanic effect. Lead sulphide nanosheets possess rock salt crystal structure, which is centrosymmetric. The symmetry can be broken by quantum confinement, asymmetric vertical interfaces and a gate electric field leading to Rashba-type band splitting in momentum space at the M points, which results in an unconventional selection mechanism for the excitation of the carriers. The effect, which is supported by simulations of the band structure using density functional theory, can be tuned by the gate electric field and by the thickness of the sheets. Spin-related electrical transport phenomena in colloidal materials open a promising pathway towards future inexpensive spintronic devices.