Tunable All Electric Spin Polarizer

TL;DR

This paper introduces a novel all-electric spin polarizer device using a four-gate quantum point contact, enabling tunable and maximized spin polarization with a broader bias range than previous designs.

Contribution

It presents a new four-gate QPC design that enhances tunability and spin polarization control compared to traditional single-gate structures.

Findings

Broader bias range for maximum spin polarization

Enhanced tunability of spin polarization

Effective all-electric control of spin states

Abstract

We propose a new device to create a tunable all-electric spin polarizer: a quantum point contact (QPC) with four gates -- two in-plane side gates in series. The first pair of gates, near the source, is asymmetrically biased to create spin polarization in the QPC channel. The second set of gates, near the drain, is symmetrically biased and that bias is varied to maximize the amount of spin polarization in the channel. The range of common mode bias on the first set of gates over which maximum spin polarization can be achieved is much broader for the four gate structure compared with the case of a single pair of in-plane side gates.