Spin Transport and Relaxation Dynamics in Single-Molecule Junctions

ongoing

Spin Transport and Relaxation Dynamics in Single-Molecule Junctions (STARDSMJ) aims at developing a toolbox of computational methods to study spin relaxation of molecular nanomagnets in the presence of charge fluctuations and external bias. This will allow us to investigate the factors affecting the spin relaxation in molecular magnets in realistic environments, namely in the operational conditions of nanoscale devices. Density Functional Theory combined with non-equilibrium Green's functions (NEGF) theory is the ab initio workhorse method for electron transport calculations. This, however, is limited to scattering from a static potential, while dynamical effects are typically included through appropriate self-energies in a perturbative way. In contrast, spin relaxation can be investigated by propagating in time master equations with parameters extracted from accurate electronic structure theory. In this case the molecule remains in a single charging state and inter-molecular interactions are of dipole-dipole nature. The main goal of STARDAM is to construct a formalism that can capture spin relaxation in an environment with fluctuating number of electrons, namely going beyond and unifying the two approaches. I will achieve this goal by developing and applying a robust theoretical scheme to solve the master equation for the transport of single-molecule junctions, where various effective spin Hamiltonians, extracted from first-principles calculations, will be used to describe the molecule.