Interference effects in phtalocyanine controlled by H-H tautomerization: a potential two-terminal unimolecular electronic switch

Abstract

We investigate the electrical transport properties of two hydrogen tautomer configurations of phthalocyanine (H2Pc) connected to cumulene and gold leads. Hydrogen tautomerization affects the electronic state of H2Pc by switching the character of molecular orbitals with the same symmetry close to the Fermi level. The near degeneracy between the HOMO and HOMO-1 leads to pronounced interference effects, causing a large change in current for the two tautomer configuratons, especially in the low-bias regime. Two types of planar junctions are considered: cumulene-H2Pc-cumulene and gold-H2Pc-gold. Both demonstrate prominent difference in molecular conductance between ON and OFF states. In addition, junctions with gold leads show pronounced negative differential resistance (NDR) at high bias voltage, as well as weak NDR at intermediate bias.

10 pages, 7 figures, accepted for publication in Physical Review B

References in corpus (10)

• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• Electrical manipulation of spin states in a single electrostatically gated transition-metal complex
• Electronic Structure of Copper Phthalocyanine: a Comparative Density Functional Theory Study
• Control of electron transport through Fano resonances in molecular wires
• Electrochemical control of quantum interference in anthraquinone-based molecular switches
• Origin of negative differential resistance in a strongly coupled single molecule-metal junction device
• A benzene interference single-electron transistor
• Critical Roles of Metal-Molecule Contacts in Electron Transport Through Molecular-wire Junctions
• Cumulene Molecular Wire Conductance from First Principles
• Quantum Interference Controlled Molecular Electronics