Switching valley filtered current directions in multi-terminal graphene systems

TL;DR

This paper proposes multi-terminal graphene devices with strain and magnetic fields to control and switch valley-polarized currents over a broad energy range, advancing valleytronics technology.

Contribution

It introduces a novel graphene setup with mechanical deformations and magnetic fields to selectively control valley-filtered current directions, including switching capabilities.

Findings

Strain and magnetic field interplay enhances valley filtering.

Threshold parameters optimize valley current switching.

Mode-matching method effectively analyzes valley transmission.

Abstract

Valley filtering processes have been explored in different graphene-based configurations and scenarios to control transport responses. Here we propose graphene multi-terminal set-ups properly designed to obtain valley filtered currents in a broad range of energy, besides the possibility of controlling their directions. We explore graphene systems with extended mechanical fold-like deformations as an opportunity to enhance valley filtered transmission. The mixing between the electronic confinement effects due to a magnetic field and strain results in a selective drive of the current components in the quantum Hall regime. We adopt the mode-matching method within the Green's function formalism, allowing the direct analysis of the strain effect on each valley transmission. We estimate a threshold map of confinement parameters, characterized by the magnetic, deformation, and set-up lengths, to optimize valley filter transport processes and the proper switch of the valley polarized current directions.