Solitons and topological superconductivity in antiferromagnet-superconductor interfaces

Jose Lado

The interplay of magnetism and superconductivity provides one of the most fertile platforms to engineer unconventional quantum matter, with the paradigmatic example of Majorana excitations in artificial topological superconductors. In particular, the potential of Majorana excitations for topological quantum computing has motivated outstanding efforts for their engineering by combining ferromagnetism, strong spin-orbit coupling, and conventional superconductivity. Here we introduce a platform alternative to those mechanisms that exploit the emergence of solitonic excitations between antiferromagnetic insulators and a conventional superconductor. First, we show that solitons at interfaces between three-dimensional antiferromagnets and superconductors can be used to engineer a two-dimensional topological superconductor, whose topological gap stems from intrinsic spin-orbit coupling [1]. Second, we show that at interfaces between two-dimensional antiferromagnetic insulators and superconductors, topological superconductivity emerges from solitons with a purely interaction- driven topological gap, requiring no spin-orbit coupling effects [2]. Ultimately, we demonstrate that many-body solitons emerge even at interfaces between quantum entangled antiferromagnets and superconductors, providing a stepping stone towards exploring emergent excitations in quantum-spin liquid superconductor junctions [3]. Our findings exemplify the potential of solitonic excitation in antiferromagnet-superconductor interfaces to engineer topological superconductivity and exotic quantum many-body states.

[1] Jose L. Lado and Manfred Sigrist, Phys. Rev. Lett. 121, 037002 (2018)
[2] Senna Luntama, Jose L. Lado and Päivi Törmä, in preparation (2020)
[3] Jose L. Lado and Manfred Sigrist, Phys. Rev. Research 2, 023347 (2020)