Spin-dependent rectification in the C 59 N molecule

Coherent spin-dependent electron transport is investigated in three conditions: (1) a C₆₀ molecule is connected to two ferromagnetic (FM) electrodes symmetrically, (2) a C₅₉N molecule is connected to two FM electrodes symmetrically and (3) a C₅₉N molecule is connected to two FM electrodes asymmetrically. This work is based on a single-band tight-binding model Hamiltonian and the Green’s function approach with the Landauer–Buttiker formalism. Electrodes used in this study are semi-infinite FM electrodes with finite cross-section. Obvious rectification effect is observed in the C₅₉N molecule which is connected to the FMelectrodes asymmetrically. This effect is more in the P alignment of FM electrodes than in AP alignment of FM electrodes. This study indicates that the rectification behaviour is due to the asymmetry in molecule and junctions. Also in this investigation tunnel magnetoresistance (TMR) is calculated for these molecules. Asymmetry is observed in TMR of C₅₉N which is coupled to the electrodes asymmetrically due to asymmetric junctions, but TMR of C₆₀ is symmetric.