Geometry-Driven Charge and Spin Transport in $\beta12$ Borophene Quantum Dots

TL;DR

This study explores how the geometry and edge configuration of $eta$12 borophene quantum dots influence charge and spin transport, revealing geometry-dependent spin filtering and transport stability for potential spintronic applications.

Contribution

It provides a detailed theoretical analysis of geometry and edge effects on charge and spin transport in borophene quantum dots, introducing design guidelines for nanoscale spintronic devices.

Findings

Armchair-connected structures show broader, more stable spin-polarized windows.

Critical lead-widths for spin filtering are approximately 1.01 nm (zigzag) and 0.87 nm (armchair).

Complete spin filtering occurs above moderate exchange field strengths.

Abstract

Theoretical research has been conducted to study how geometry affects charge and spin transport in $\beta\mathrm{12}$ borophene quantum dots, which are confined systems. The study examined two distinct central regions, which included a circular disc and a regular hexagonal area that connected to semi-infinite zigzag and armchair borophene nanoribbon leads. The system was described by a five-band tight-binding Hamiltonian parameterized using first-principles data, and the transport properties were calculated within the non-equilibrium Green's function framework. Spin resolved transmissions and spin polarization were computed for a range of lead widths and proximity-induced exchange field strengths. The analysis revealed distinct transport characteristics determined by geometry and edge configuration: armchair-connected structures exhibited broader and more stable fully spin-polarized windows compared with zigzag-connected counterparts. Furthermore, critical lead-width thresholds ($\approx 1.01$ nm for zigzag and $\approx 0.87$ nm for armchair) and a moderate exchange field above which complete spin filtering occurs were identified. The results highlight the strong influence of edge termination and confinement geometry on transport properties and provide useful design guidelines for developing borophene-based nanoscale spintronic devices.