Signatures of Andreev Blockade in a Double Quantum Dot Coupled to a Superconductor
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Signatures of Andreev Blockade in a Double Quantum Dot Coupled to a Superconductor. / Zhang, Po; Wu, Hao; Chen, Jun; Khan, Sabbir A.; Krogstrup, Peter; Pekker, David; Frolov, Sergey M.
In: Physical Review Letters, Vol. 128, No. 4, 046801, 28.01.2022.Research output: Contribution to journal › Letter › Research › peer-review
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TY - JOUR
T1 - Signatures of Andreev Blockade in a Double Quantum Dot Coupled to a Superconductor
AU - Zhang, Po
AU - Wu, Hao
AU - Chen, Jun
AU - Khan, Sabbir A.
AU - Krogstrup, Peter
AU - Pekker, David
AU - Frolov, Sergey M.
N1 - Funding Information: S. F. and D. P. are supported by NSF PIRE-1743717. S. F. is supported by NSF DMR-1906325, ONR, and ARO. P. K. is supported by European Union Horizon 2020 research and innovation program under the Marie Skłodowska-Curie Grant No. 722176 (INDEED), Microsoft Quantum and the European Research Council (ERC) under Grant No. 716655 (HEMs-DAM). Publisher Copyright: © 2022 American Physical Society
PY - 2022/1/28
Y1 - 2022/1/28
N2 - We investigate an electron transport blockade regime in which a spin triplet localized in the path of current is forbidden from entering a spin-singlet superconductor. To stabilize the triplet, a double quantum dot is created electrostatically near a superconducting Al lead in an InAs nanowire. The quantum dot closest to the normal lead exhibits Coulomb diamonds, and the dot closest to the superconducting lead exhibits Andreev bound states and an induced gap. The experimental observations compare favorably to a theoretical model of Andreev blockade, named so because the triplet double dot configuration suppresses Andreev reflections. Observed leakage currents can be accounted for by finite temperature. We observe the predicted quadruple level degeneracy points of high current and a periodic conductance pattern controlled by the occupation of the normal dot. Even-odd transport asymmetry is lifted with increased temperature and magnetic field. This blockade phenomenon can be used to study spin structure of superconductors. It may also find utility in quantum computing devices that use Andreev or Majorana states.
AB - We investigate an electron transport blockade regime in which a spin triplet localized in the path of current is forbidden from entering a spin-singlet superconductor. To stabilize the triplet, a double quantum dot is created electrostatically near a superconducting Al lead in an InAs nanowire. The quantum dot closest to the normal lead exhibits Coulomb diamonds, and the dot closest to the superconducting lead exhibits Andreev bound states and an induced gap. The experimental observations compare favorably to a theoretical model of Andreev blockade, named so because the triplet double dot configuration suppresses Andreev reflections. Observed leakage currents can be accounted for by finite temperature. We observe the predicted quadruple level degeneracy points of high current and a periodic conductance pattern controlled by the occupation of the normal dot. Even-odd transport asymmetry is lifted with increased temperature and magnetic field. This blockade phenomenon can be used to study spin structure of superconductors. It may also find utility in quantum computing devices that use Andreev or Majorana states.
U2 - 10.1103/PhysRevLett.128.046801
DO - 10.1103/PhysRevLett.128.046801
M3 - Letter
C2 - 35148137
AN - SCOPUS:85124500963
VL - 128
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 4
M1 - 046801
ER -
ID: 307083104