Aharonov-Bohm effect in a biphenyl system: relations between torsion angle, magnetic flux and electrical current

Abstract

This work presents a theoretical investigation of charge transport through a two-terminal biphenyl device under an external magnetic field, focusing on the Aharonov–Bohm effect. The Landauer formalism is employed, with the electronic structure described at the tight-binding (TB) level and the self-energies treated within the wide band limit approximation. Additionally, a decimation technique is applied to enable an analytical treatment. The influence of magnetic flux through the molecular rings is examined in two distinct scenarios: (i) varying the magnitude of the magnetic field while keeping the torsion angle fixed, and (ii) varying the torsion angle while maintaining a constant magnetic field. In the first case, we observe an increased electrical current with increasing magnetic flux. In the second case, the current increases as the magnetic flux decreases. By analyzing the dependence of the electronic current on the torsion angle and the magnetic flux, we uncover key mechanisms underlying quantum interference in this system.