Spin-Polarizing Electron Beam Splitter from Crossed Graphene Nanoribbons

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Technologies

Background:

• Graphene nanoribbons (GNRs) have been theoretically proposed as efficient electron beam splitters.
• These devices aim for coherent splitting of electron waves with minimal back-scattering.
• The role of electron-electron interactions, specifically Coulomb repulsion, in GNR properties is crucial.

Purpose of the Study:

• To investigate electron beam splitting in crossed zigzag GNR junctions.
• To analyze the impact of Coulomb repulsion and resulting spin-polarized edge states on beam splitting.
• To explore the potential of GNRs for spintronics and quantum information technologies.

Main Methods:

• Theoretical investigation using mean-field theory.
• Analysis of narrow zigzag graphene nanoribbon junctions.
• Scrutiny of electron wave splitting, back-scattering, and spin polarization phenomena.

Main Results:

• The electron beam-splitting effect persists even with the correlation gap induced by Coulomb repulsion.
• A spin-dependent scattering potential emerges, leading to spin-polarized electron transmission.
• Near-perfect spin polarization is achievable by connecting multiple GNR junctions in series.

Conclusions:

• Crossed graphene nanoribbon junctions are promising for coherent electron beam splitting.
• The interplay of Coulomb repulsion and GNR geometry enables spin polarization of transmitted electrons.
• GNRs represent valuable building blocks for spintronics, quantum interferometry, and entanglement applications.