Superconducting atomic contacts under microwave irradiation

M. Chauvin (1) , P. Vom Stein (1) , H. Pothier (1) , P. Joyez (1) , M. E. Huber (2) , Daniel Esteve (1) , C. Urbina (1)

1 QUANTRONICS - Quantronics Group
2 Department of Physics [Denver]

We have measured the effect of microwave irradiation on the dc current-voltage characteristics of superconducting atomic contacts. The interaction of the external field with the ac supercurrents leads to replicas of the supercurrent peak, the well known Shapiro resonances. The observation of supplementary fractional resonances for contacts containing highly transmitting conduction channels reveals their non-sinusoidal current-phase relation. The resonances sit on a background current which is itself deeply modified, as a result of photon assisted multiple Andreev reflections. The results provide firm support for the full quantum theory of transport between two superconductors based on the concept of Andreev bound states.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]; Supraconductivité [cond-mat.supr-con]

M. Chauvin, P. Vom Stein, H. Pothier, P. Joyez, M. E. Huber, et al.. Superconducting atomic contacts under microwave irradiation. Physical Review Letters, 2006, 97, pp.067006. ⟨10.1103/PhysRevLett.97.067006⟩. ⟨hal-00090300⟩