TY - JOUR
T1 - Nonequilibrium Transport through a Spinful Quantum Dot with Superconducting Leads
AU - Andersen, Brian Møller
AU - Flensberg, Karsten
AU - Koerting, Verena
AU - Paaske, Jens
PY - 2011/12/14
Y1 - 2011/12/14
N2 - We study the nonlinear cotunneling current through a spinful quantum dot contacted by two superconducting leads. Applying a general nonequilibrium Green function formalism to an effective Kondo model, we study the rich variation in the IV characteristics with varying asymmetry in the tunnel coupling to source and drain electrodes. The current is found to be carried, respectively, by multiple Andreev reflections in the symmetric limit, and by spin-induced Yu-Shiba-Rusinov bound states in the strongly asymmetric limit. The interplay between these two mechanisms leads to qualitatively different IV characteristics in the crossover regime of intermediate symmetry, consistent with recent experimental observations of negative differential conductance and repositioned conductance peaks in subgap cotunneling spectroscopy.
AB - We study the nonlinear cotunneling current through a spinful quantum dot contacted by two superconducting leads. Applying a general nonequilibrium Green function formalism to an effective Kondo model, we study the rich variation in the IV characteristics with varying asymmetry in the tunnel coupling to source and drain electrodes. The current is found to be carried, respectively, by multiple Andreev reflections in the symmetric limit, and by spin-induced Yu-Shiba-Rusinov bound states in the strongly asymmetric limit. The interplay between these two mechanisms leads to qualitatively different IV characteristics in the crossover regime of intermediate symmetry, consistent with recent experimental observations of negative differential conductance and repositioned conductance peaks in subgap cotunneling spectroscopy.
U2 - 10.1103/PhysRevLett.107.256802
DO - 10.1103/PhysRevLett.107.256802
M3 - Journal article
C2 - 22243100
VL - 107
SP - 256802
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 25
ER -