Tuning spin filtering by anchoring groups in benzene derivative molecular junctions

Dongzhe Li (1) , Yannick J Dappe (2) , Alexander Smogunov (1)

1 SPCSI - Service de Physique et de Chimie des Surfaces et Interfaces
2 GMT - Groupe Modélisation et Théorie

One of important issues of molecular spintronics is the control and 1 manipulation of charge transport and, in particular, its spin polarization through 2 single-molecule junctions. Using ab initio calculations, we explore spin-polarized 3 electron transport across single benzene derivatives attached with six different 4 anchoring groups (S, CH 3 S, COOH, CNH 2 NH, NC and NO 2) to Ni(111) electrodes. 5 We find that molecule-electrode coupling, conductance and spin polarization (SP) of 6 electric current can be modified significantly by anchoring groups. In particular, a 7 high spin polarization (SP > 80%) and a giant magnetoresistance (MR > 140%) can be 8 achieved for NO 2 terminations and, more interestingly, SP can be further enhanced (up 9 to 90%) by a small voltage. The S and CH 3 S systems, on the contrary, exhibit rather 10 low SP while intermediate values are found for COOH and CNH 2 NH groups.The results 11 are analyzed in detail and explained by orbital symmetry arguments, hybridization 12 and spatial localization of frontier molecular orbitals. We hope that our comparative 13 and systematic studies will provide a valuable quantitative information for future 14 experimental measurements on that kind of systems and will be useful for designing 15 high-performance spintronics devices. 16

Mots clés: Molecular spintronics; NEGF-DFT calculations; Spin filtering; Single-

Domaines: Physique [physics]

Dongzhe Li, Yannick J Dappe, Alexander Smogunov. Tuning spin filtering by anchoring groups in benzene derivative molecular junctions. Journal of Physics: Condensed Matter, 2019, 31 (40), pp.405301. ⟨10.1088/1361-648X/ab2846⟩. ⟨hal-02336477⟩