Pure spin current generated in thermally driven molecular magnetic junctions: a promising mechanism for thermoelectric conversion

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2019, Vol.7 (32), p.1937-1944
• Main Authors: Wu, Dan, Cao, Xuan-Hao, Chen, Shi-Zhang, Tang, Li-Ming, Feng, Ye-Xin, Chen, Ke-Qiu, Zhou, Wu-Xing
• Format: Article
• Language: English
• Subjects: Dimers; Energy conservation; First principles; Green's functions; Seebeck effect; Spintronics; Temperature gradients; Thermoelectricity; Transition metals; Transport properties
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta04642a

Pure spin current is expected to be utilized for designing energy-saving devices. Using first-principles calculations in combination with a non-equilibrium Green's function method, the spin-dependent thermoelectric transport properties of metallocene dimer-based molecular junctions are investigated. The results show that spin-polarized currents can be achieved when a temperature difference is applied in molecular structures. It is found that the spin-polarized transport properties are different when transition metals in the dimers are different. It is interesting that a negative differential thermoelectric resistance and a perfect spin filtering effect can be found in chromocene dimer-based and manganocene dimer-based molecular junctions. Moreover, one key finding is that a pure spin current can be obtained in a cobaltocene dimer-based molecular junction, in which the spin-dependent Seebeck coefficient is larger than the charge Seebeck coefficient. These interesting results indicate that metallocene dimer-based molecular junctions have potential applications in future thermal spintronic and spin thermoelectric devices. Thermally driven magnetic-molecular junctions can be designed as pure spin current generators, spin thermoelectric devices or thermal-spin converters.