Signatures of Majorana Bound States in the Diffraction Patterns of Extended Superconductor-Topological Insulator-Superconductor Josephson Junctions

Fuente: arXiv
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Autores principales: Yue, Guang, Zhang, Can, Huemiller, Erik D., Montone, Jessica H., Arias, Gilbert R., Wild, Drew G., Zhang, Jered Y., Hamilton, David R., Yuan, Xiaoyu, Yao, Xiong, Jain, Deepti, Moon, Jisoo, Salehi, Maryam, Koirala, Nikesh, Oh, Seongshik, Van Harlingen, Dale J.
Formato: Preprint
Publicado: 2023
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author Yue, Guang
Zhang, Can
Huemiller, Erik D.
Montone, Jessica H.
Arias, Gilbert R.
Wild, Drew G.
Zhang, Jered Y.
Hamilton, David R.
Yuan, Xiaoyu
Yao, Xiong
Jain, Deepti
Moon, Jisoo
Salehi, Maryam
Koirala, Nikesh
Oh, Seongshik
Van Harlingen, Dale J.
author_facet Yue, Guang
Zhang, Can
Huemiller, Erik D.
Montone, Jessica H.
Arias, Gilbert R.
Wild, Drew G.
Zhang, Jered Y.
Hamilton, David R.
Yuan, Xiaoyu
Yao, Xiong
Jain, Deepti
Moon, Jisoo
Salehi, Maryam
Koirala, Nikesh
Oh, Seongshik
Van Harlingen, Dale J.
contents In an extended superconductor-topological insulator-superconductor (S-TI-S) Josephson junction in a magnetic field, localized Majorana bound states (MBS) are predicted to exist at the cores of Josephson vortices where the local phase difference across the junction is an odd-multiple of $π$. These states contribute a supercurrent with a $4π$-periodic current-phase relation (CPR) that adds to the conventional $2π$-periodic sinusoidal CPR. In this work, we present a comprehensive experimental study of the critical current vs. applied magnetic field diffraction patterns of lateral Nb-Bi$_2$Se$_3$-Nb Josephson junctions. We compare our observations to a model of the Josephson dynamics in the S-TI-S junction system to explore what feature of MBS are, or are not, exhibited in these junctions. Consistent with the model, we find several distinct deviations from a Fraunhofer diffraction pattern that is expected for a uniform sin$(ϕ)$ CPR. In particular, we observe abrupt changes in the diffraction pattern at applied magnetic fields in which the current-carrying localized MBS are expected to enter the junction, and a lifting of the odd-numbered nodes consistent with a $4π$-periodic sin$(ϕ/2)$-component in the CPR. We also see that although the even-numbered nodes often remain fully-formed, we sometimes see deviations that are consistent with quasiparticle-induced fluctuations in the parity of the MBS pairs that encodes quantum information.
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institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Signatures of Majorana Bound States in the Diffraction Patterns of Extended Superconductor-Topological Insulator-Superconductor Josephson Junctions
Yue, Guang
Zhang, Can
Huemiller, Erik D.
Montone, Jessica H.
Arias, Gilbert R.
Wild, Drew G.
Zhang, Jered Y.
Hamilton, David R.
Yuan, Xiaoyu
Yao, Xiong
Jain, Deepti
Moon, Jisoo
Salehi, Maryam
Koirala, Nikesh
Oh, Seongshik
Van Harlingen, Dale J.
Superconductivity
Mesoscale and Nanoscale Physics
In an extended superconductor-topological insulator-superconductor (S-TI-S) Josephson junction in a magnetic field, localized Majorana bound states (MBS) are predicted to exist at the cores of Josephson vortices where the local phase difference across the junction is an odd-multiple of $π$. These states contribute a supercurrent with a $4π$-periodic current-phase relation (CPR) that adds to the conventional $2π$-periodic sinusoidal CPR. In this work, we present a comprehensive experimental study of the critical current vs. applied magnetic field diffraction patterns of lateral Nb-Bi$_2$Se$_3$-Nb Josephson junctions. We compare our observations to a model of the Josephson dynamics in the S-TI-S junction system to explore what feature of MBS are, or are not, exhibited in these junctions. Consistent with the model, we find several distinct deviations from a Fraunhofer diffraction pattern that is expected for a uniform sin$(ϕ)$ CPR. In particular, we observe abrupt changes in the diffraction pattern at applied magnetic fields in which the current-carrying localized MBS are expected to enter the junction, and a lifting of the odd-numbered nodes consistent with a $4π$-periodic sin$(ϕ/2)$-component in the CPR. We also see that although the even-numbered nodes often remain fully-formed, we sometimes see deviations that are consistent with quasiparticle-induced fluctuations in the parity of the MBS pairs that encodes quantum information.
title Signatures of Majorana Bound States in the Diffraction Patterns of Extended Superconductor-Topological Insulator-Superconductor Josephson Junctions
topic Superconductivity
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2311.16489