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arXiv · 0911.1782

Fractionalization in Superconductor Josephson Junction Arrays Hinged by Quantum Spin Hall edges

Cenke Xu·Liang Fu
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Abstract

In this paper we study a novel superconductor-ferromagnet-superconductor (SC-FM-SC) Josephson junction array deposited on top of a two-dimensional quantum spin Hall (QSH) insulator. The existence of Majorana bound states at the interface between SC and FM gives rise to charge-e tunneling, in addition to the usual charge-2e Cooper pair tunneling, between neighboring superconductor islands. Moreover, because Majorana fermions encode the information of charge number parity, an exact Z_2 gauge structure naturally emerges and leads to many new insulating phases, including a deconfined phase where electrons fractionalize into charge-e bosons and topological defects. A new superconductor-insulator transition has also been found.

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Cenke Xu, Liang Fu. 2010-03-30. Fractionalization in Superconductor Josephson Junction Arrays Hinged by Quantum Spin Hall edges. https://doi.org/10.1103/physrevb.81.134435

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