Transport Signatures of Quasiparticle Poisoning in a Majorana Island

We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition to the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e in gate voltage, consistent with transport through an excited (poisoned) stat...

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Bibliographic Details
Published in:Physical review letters 2017-03, Vol.118 (13), p.137701-137701, Article 137701
Main Authors: Albrecht, S M, Hansen, E B, Higginbotham, A P, Kuemmeth, F, Jespersen, T S, Nygård, J, Krogstrup, P, Danon, J, Flensberg, K, Marcus, C M
Format: Article
Language:English
Subjects:
Coulomb friction
Coupling
Diamonds
Electric potential
Fluctuation
Islands
Transport
Voltage
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Summary:We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition to the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e in gate voltage, consistent with transport through an excited (poisoned) state of the island. Comparison to a simple model yields an estimate of parity lifetime for the strongly coupled island (∼1  μs) and sets a bound for a weakly coupled island (>10  μs). Fluctuations in the gate-voltage spacing of Coulomb peaks at high field, reflecting Majorana hybridization, are enhanced by the reduced lever arm at strong coupling. When converted from gate voltage to energy units, fluctuations are consistent with previous measurements.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.118.137701