Mechano-switching devices from carbon wire-carbon nanotube junctions

Well-known conductive molecular wires, such as cumulene or polyyne, provide a model for interconnecting molecular electronics circuits. In recent experiments, the appearance of carbon wire bridging between two-dimensional electrodes, i.e., graphene sheets, was observed [C. Jin et al., Phys. Rev. Lett. 102, 205501 (2009)], thus demonstrating a mechanical way of producing cumulene. In this work, we studied the structure and conductance of carbon wire suspended between carbon nanotubes (CNTs) of different chiralities (zigzag and armchair), and corresponding conductance variation upon stretching. We found that the geometric structure of the carbon wire bridging CNTs was similar to the experimentally observed structures in carbon wire obtained between graphene electrodes. We show a way to modulate conductance by changing bridging sites between carbon wire and CNTs without breaking the wire. Observed current modulation via cumulene wire stretching or elongation together with CNT junction stability makes this a promising candidate for use in mechano-switching devices for molecular nanoelectronics. DOI: 10.1103/PhysRevB.87.155434