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arXiv · 0909.0867

The tunneling conductance between a superconducting STM tip and an out-of-equilibrium carbon nanotube

Cristina Bena
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Abstract

We calculate the current and differential conductance for the junction between a superconducting (SC) STM tip and a Luttinger liquid (LL). For an infinite single-channel LL, the SC coherence peaks are preserved in the tunneling conductance for interactions weaker than a critical value, while for strong interactions (g <0.38), they disappear and are replaced by cusp-like features. For a finite-size wire in contact with non-interacting leads, we find however that the peaks are restored even for extremely strong interactions. In the presence of a source-drain voltage the peaks/cusps split, and the split is equal to the voltage. At zero temperature, even very strong interactions do not smear the two peaks into a broader one; this implies that the recent experiments of Y.-F. Chen et. al. (Phys. Rev. Lett. 102, 036804 (2009)) do not rule out the existence of strong interactions in carbon nanotubes.

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Cristina Bena. 2009-09-04. The tunneling conductance between a superconducting STM tip and an out-of-equilibrium carbon nanotube. https://doi.org/10.1103/physrevb.82.035312

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