Designing bifuncitonal molecular devices with a metalloporphyrin dimer

• Published in: Physical chemistry chemical physics : PCCP 2020-02, Vol.22 (7), p.48-485
• Main Authors: Xia, Ying, Shuai, Ling, Wang, Yiping, Ma, Yao, Han, Lingyun, Qiu, Ming, Zhang, Zhenhua, Leung, Michael K. H
• Format: Article
• Language: English
• Subjects: Cobalt; Copper; Devices; Dimers; Electric potential; Electron spin; Filtration; First principles; Giant magnetoresistance; Iron; Magnetic moments; Magnetic properties; Magnetism; Magnetoresistance; Magnetoresistivity; Manganese; Molecular structure; Organic chemistry; Transport properties; Voltage
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c9cp05079e

Many organic molecules have unique magnetic properties and can potentially serve as excellent molecular spin devices, which is worth exploring deeply. Here, the spin transport properties of Mn, Fe, Co and Cu porphyrin dimer devices are investigated based on the first principles method. The spin filtering efficiencies of these molecular devices are maintained at 100% within certain applied voltage ranges and magnetoresistance ratios are higher than 10 8 % which increase as the voltage increases. To explain the excellent spin-filtering and giant magnetoresistance effects, analysis of spin electron densities and transmission spectra indicates that magnetic properties are mainly contributed by the metal atoms and their neighbouring N atoms. From the transmission pathway studies, spin electrons come mainly through the π-conjugated structure of the metal porphyrin ring. Interestingly, in the Cu porphyrin dimer device, magnetic moments of the Cu-N structure in the Cu porphyrin dimer device show spin behaviors different from those of Mn, Fe and Co porphyrin dimer devices. The metalloporphyrin dimer devices have high spin filtering efficiencies and magnetoresistance ratios exceeding 10 8 %.