Theoretical Investigation of Chemical Spin Doping into Single Porphyrin Junctions toward Ultrahigh-Sensitive Nitric Oxide Sensor
We theoretically study chemical spin doping into single porphyrins connected to nanoelectrodes via benzenethiols, ethynyl-benzenethiols, and vinyl-benzenethiols using the adsorption of a nitric oxide (NO) molecule. For all three anchoring groups, the adsorption of a NO molecule injects one spin into...
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| Published in | Japanese Journal of Applied Physics Vol. 51; no. 4; pp. 045202 - 045202-6 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.04.2012
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| Online Access | Get full text |
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| Summary: | We theoretically study chemical spin doping into single porphyrins connected to nanoelectrodes via benzenethiols, ethynyl-benzenethiols, and vinyl-benzenethiols using the adsorption of a nitric oxide (NO) molecule. For all three anchoring groups, the adsorption of a NO molecule injects one spin into single-molecule junctions and produces antiferromagnetic interactions between the injected spin and the original spins at the junctions, resulting in a decrease in the spin-polarized currents. We found that the magnitude of change in the spin-polarized current significantly depends on the type of anchoring groups; the magnitude is ordered by the following anchoring group: vinyl-benzenethiol $>$ ethynyl-benzenethiol $>$ benzenethiol. In particular, for vinyl-benzenethiol, spin doping causes not only $\pi$ electron localization on molecular orbitals but also structural change. |
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| Bibliography: | (a) Schematic diagram of chemical spin doping into a single-molecule junction consisting of porphyrin-based molecules and gold electrodes using the adsorption of a NO molecule. Molecular structures of (b) FeTPP, (c) FeTPEP, and (d) FeTPVP. Optimized molecular structures of (a) FeTPP, (b) FeTPEP, (c) FeTPVP, (d) NO-doped FeTPP, (e) NO-doped FeTPEP, and (f) NO-doped FeTPVP. Dihedral angles ($\theta$) are defined as the angles between the molecular planes of the porphyrins and the anchoring benzenes. Transmission coefficient spectra of nondoped and NO-doped (a) FeTPP, (b) FeTPEP, and (c) FeTPVP. $E_{\text{F}}$ represents the Fermi energy of the electrodes. MPSH of the HOMO$-$1, HOMO, and LUMO for nondoped and NO-doped (a) FeTPP, (b) FeTPEP, and (c) FeTPVP, along with the level number of the MPSH. Blue and red isosurfaces represent positive and negative isovalues, respectively. Isosurfaces have a value of 0.02. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.1143/JJAP.51.045202 |