Coherent multiple Andreev reflections and current resonances in SNS quantum point contacts
Artikel i vetenskaplig tidskrift, 2001

We study coherent multiple Andreev reflections in ballistic superconductor-normal conductor-superconductor junctions with a quantum point contact in the normal region of the junction (superconductor-normal region-quantum point contact-normal region-superconductor) with arbitrary transparency. The presence of superconducting bound states in these junctions gives rise to great enhancement of the subgap current. The effect is most pronounced in low-transparency junctions, D≪1, and in the interval of applied voltage Δ/2<eV<2Δ, where the amplitude of the current structures is proportional to the first power of the junction transparency D. The resonant current structures consist of steps and oscillations of the two-particle current and also of multiparticle resonance peaks. The positions of the two-particle current structures have a pronounced temperature dependence, which scales with Δ(T), while the positions of the multiparticle resonances have a weak temperature dependence, being mostly determined by the junction geometry. Despite the large, resonant two-particle current, the excess current at large voltage is small and proportional to D2.


Åke Ingerman

Institutionen för mikroelektronik och nanovetenskap

Göran Johansson

Institutionen för mikroelektronik och nanovetenskap, Tillämpad kvantfysik

Vitaly Shumeiko

Institutionen för mikroelektronik och nanovetenskap, Tillämpad kvantfysik

Göran Wendin

Institutionen för mikroelektronik och nanovetenskap, Tillämpad kvantfysik

Physical Review B - Condensed Matter and Materials Physics

24699950 (ISSN) 24699969 (eISSN)

Vol. 64 144504



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