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arXiv · 2204.11737

Phase diagram of superconductivity in the integer quantum Hall regime

Jonathan Schirmer·C. -X. Liu·J. K. Jain
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Abstract

An interplay between pairing and topological orders has been predicted to give rise to superconducting states supporting exotic emergent particles, such as Majorana particles obeying non-Abelian braid statistics. We consider a system of spinless electrons on a Hofstadter lattice with nearest neighbor attractive interaction, and solve the mean-field Bogoliubov-de Gennes equations in a self-consistent fashion, leading to gauge invariant solutions that display a rich phase diagram as a function of the chemical potential, magnetic field and the interaction. As the strength of the attractive interaction is increased, the system first makes a transition from a quantum Hall phase to a skyrmion lattice phase that is fully gapped in the bulk but has topological chiral edge current, characterizing a topologically non-trivial state. This is followed by a vortex phase in which the vortices carrying Majorana modes form a lattice; the spectrum contains a low-energy Majorana band arising from the coupling between neighboring vortex-core Majorana modes but does not have chiral edge currents. For some parameters, a dimer vortex lattice occurs with no low energy Majorana band. The experimental feasibility and the observable consequences of skyrmions as well as Majorana fermions are indicated.

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Jonathan Schirmer, C. -X. Liu, J. K. Jain. 2022-04-25. Phase diagram of superconductivity in the integer quantum Hall regime. https://doi.org/10.1073/pnas.2202948119

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