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arXiv · 1611.05440

Reduction of electron repulsion and enhancement of $T_{c}$ in small diffusive superconducting grains

Sabyasachi Tarat·Yuval Oreg·Yoseph Imry
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Abstract

The superconducting properties of small metallic grains has been a topic of active research for half a century now. Early experiments demonstrated a remarkable rise in the critical temperature, $T_{c}$, with reducing grain size in a variety of materials. In two dimensional diffusive superconductors, $T_{c}$ is decreased due to enhanced Coulomb repulsion. We propose that in finite size grains, the diffusive enhancement of the Coulomb repulsion is weakened and leads ultimately to an increase in $T_{c}$ in isolated, disordered two dimensional grains. Our mechanism is superimposed on the possible enhancement in $T_{c}$ due to the change in the density of states of finite size systems.

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Sabyasachi Tarat, Yuval Oreg, Yoseph Imry. 2017-03-15. Reduction of electron repulsion and enhancement of $T_{c}$ in small diffusive superconducting grains. https://doi.org/10.1103/physrevlett.118.157001

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