Bias-controllable intrinsic spin polarization in a quantum dot

TL;DR

This paper introduces a bias-controlled quantum dot scheme leveraging spin-orbit interaction to achieve large, controllable electron spin polarization without magnetic fields, suitable for practical applications.

Contribution

The authors propose a novel, bias-tunable method for electron spin polarization in quantum dots that is efficient, controllable, and compatible with current technology.

Findings

Large spin polarization achievable with weak spin-orbit interaction

Spin polarization is enhanced by electron-electron interactions and multiple energy levels

The scheme operates without magnetic fields or ferromagnetic materials

Abstract

We propose a novel scheme to efficiently polarize and manipulate the electron spin in a quantum dot. This scheme is based on the spin-orbit interaction and it possesses following advantages: (1) The direction and the strength of the spin polarization is well controllable and manipulatable by simply varying the bias or the gate voltage. (2) The spin polarization is quite large even with a weak spin-orbit interaction. (3) Both electron-electron interaction and multi-energy levels do not weaken but strengthen the spin polarization. (4) It has the short spin flip time. (5) The device is free of a magnetic field or a ferromagnetic material. (6) It can be easily realized with present technology.