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arXiv · 2306.11200

Nematic Bogoliubov Fermi surfaces from magnetic toroidal order in FeSe$_{1-x}$S$_x$

Hao Wu·Adil Amin·Yue Yu·Daniel F. Agterberg
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Abstract

Recently it has been argued that the superconducting state of FeSe$_{1-x}$S$_x$ exhibits Bogoliubov Fermi surfaces for $x>0.17$. These Bogoliubov Fermi surfaces appear together with broken time-reversal symmetry and surprisingly demonstrate nematic behavior in a structurally tetragonal phase. Through a symmetry-based analysis of Bogoliubov Fermi surfaces that can arise from broken time-reversal symmetry, we argue that the likely origin of time-reversal symmetry breaking is due to magnetic toroidal order. We show that this magnetic toroidal order naturally appears as a consequence of either static N\'{e}el antiferromagnetic order or due to the formation of a spontaneous pair density wave superconducting order. Finally, we reveal that independent of the presence of Bogoliubov Fermi surfaces, supercurrents will induce N\'{e}el magnetic order in many Fe-based superconductors.

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Hao Wu, Adil Amin, Yue Yu, Daniel F. Agterberg. 2023-06-19. Nematic Bogoliubov Fermi surfaces from magnetic toroidal order in FeSe$_{1-x}$S$_x$. https://doi.org/10.1103/physrevb.109.l220501

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