Remarkable modulation of the spin transport properties of transition metal dibenzotetraaza[14]annulenes by adsorption of oxygen

Here, the spin transport properties of molecular devices comprised of a transition metal-dibenzo-tetraaza[14]annulene complex (TM-DBTAA, TM=Co, Cu, Ni) connected to two single-walled carbon nan-otube (SWCNT) electrodes have been theoretically investigated by using the first-principles method. In addition, the effect of O2 adsorption on the TM atom on the spin transport properties of the investigated devices is inspected. The calculations reveal that Co-DBTAA behaves as a spin filter with SFE close to 100%. Upon O2 adsorption, the spin polarization of the current for Co-DBTAA is changed from spin-down to spin-up with the magnitude of SFE nearly unchanged. More interestingly, for the spin non-polarized and nonconducting Ni-DBTAA, the adsorption of an O2 molecule induces a spin-up polarized current with remarkable SFE larger than 90%. This work is helpful for future designing of molecular spin filters as well as gas sensors. (c) 2023 Elsevier B.V. All rights reserved.