Complete spin filtering in molecular junctions by quantum interference

报告题目:Complete spin filtering in molecular junctions by quantum interference

报告人:Dr. Dongzhe Li (University of Konstanz)



摘要:Generating efficient and highly spin-polarized currents through nanoscale junctions is essential in the field of nanoelectronics and spintronics. In this talk, coupling state-of-the-art ab initio electron transport calculations and shot noise measurements, I will give the first demonstration to obtain complete spin filtering in molecular junctions based on symmetry arguments and spin-dependent quantum interference effects. In particular, a mechanical strain can be used to modify the nanojunction symmetry switching on or off new conduction channels. I will first illustrate the physical mechanism on the basic molecular junction of benzene and generalize it in vanadocene junction to explain recent shot noise measurements of an almost fully open spin-polarized transmission channel. Remarkably, the majority-spin conductance is completely suppressed due to destructive quantum interference, resulting in perfect spin filtering. Therefore, a single molecule act as a half-metallic conductor although free organic molecule is actually an insulator. These findings pave the way for spin transport manipulations by quantum interference at the single nanometer scale.