Berry‐Phase Effect in Single‐Molecule Magnets: Analytical and Numerical Results

Herein, transport signatures of quantum interference on the current through a single‐molecule magnet transistor tunnel coupled to oppositely polarized leads in the presence of a local transverse and longitudinal magnetic field are theoretically and numerically investigated. These calculations are based on a density matrix approach where the ground‐state energy splitting induced by tunneling of the spin between different paths is treated with the aid of perturbation theory. Using this approach, it is shown that it is possible to use an effective Hamiltonian, which describes the Berry‐phase interference as a function of the transverse magnetic field, which completely blocks the current flow when the single‐molecule magnet is placed between oppositely polarized leads. Finally, this effective Hamiltonian is used in an open‐source Python software (QmeQ) that allows us to calculate the current through the single‐molecule magnet with oppositely polarized leads tunnel coupled to the single‐molecule magnet. The analytical results are well reproduced by numerical simulations.