Effect of Zeeman coupling on the Majorana vortex modes in iron-based topological superconductors

A. Ghazaryan, P.L.S. Lopes, P. Hosur, M.J. Gilbert, P. Ghaemi, Physical Review B 101 (2020) 020504.


Journal Article | Published | English

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Author
Ghazaryan, AregIST Austria ; Lopes, P. L.S.; Hosur, Pavan; Gilbert, Matthew J.; Ghaemi, Pouyan
Department
Abstract
In the superconducting regime of FeTe(1−x)Sex, there exist two types of vortices which are distinguished by the presence or absence of zero-energy states in their core. To understand their origin, we examine the interplay of Zeeman coupling and superconducting pairings in three-dimensional metals with band inversion. Weak Zeeman fields are found to suppress intraorbital spin-singlet pairing, known to localize the states at the ends of the vortices on the surface. On the other hand, an orbital-triplet pairing is shown to be stable against Zeeman interactions, but leads to delocalized zero-energy Majorana modes which extend through the vortex. In contrast, the finite-energy vortex modes remain localized at the vortex ends even when the pairing is of orbital-triplet form. Phenomenologically, this manifests as an observed disappearance of zero-bias peaks within the cores of topological vortices upon an increase of the applied magnetic field. The presence of magnetic impurities in FeTe(1−x)Sex, which are attracted to the vortices, would lead to such Zeeman-induced delocalization of Majorana modes in a fraction of vortices that capture a large enough number of magnetic impurities. Our results provide an explanation for the dichotomy between topological and nontopological vortices recently observed in FeTe(1−x)Sex.
Publishing Year
Date Published
2020-01-13
Journal Title
Physical Review B
Volume
101
Issue
2
Article Number
020504
ISSN
eISSN
IST-REx-ID

Cite this

Ghazaryan A, Lopes PLS, Hosur P, Gilbert MJ, Ghaemi P. Effect of Zeeman coupling on the Majorana vortex modes in iron-based topological superconductors. Physical Review B. 2020;101(2):020504. doi:10.1103/PhysRevB.101.020504
Ghazaryan, A., Lopes, P. L. S., Hosur, P., Gilbert, M. J., & Ghaemi, P. (2020). Effect of Zeeman coupling on the Majorana vortex modes in iron-based topological superconductors. Physical Review B, 101(2), 020504. https://doi.org/10.1103/PhysRevB.101.020504
Ghazaryan, Areg, P. L.S. Lopes, Pavan Hosur, Matthew J. Gilbert, and Pouyan Ghaemi. “Effect of Zeeman Coupling on the Majorana Vortex Modes in Iron-Based Topological Superconductors.” Physical Review B 101, no. 2 (2020): 020504. https://doi.org/10.1103/PhysRevB.101.020504.
A. Ghazaryan, P. L. S. Lopes, P. Hosur, M. J. Gilbert, and P. Ghaemi, “Effect of Zeeman coupling on the Majorana vortex modes in iron-based topological superconductors,” Physical Review B, vol. 101, no. 2, p. 020504, 2020.
Ghazaryan A, Lopes PLS, Hosur P, Gilbert MJ, Ghaemi P. 2020. Effect of Zeeman coupling on the Majorana vortex modes in iron-based topological superconductors. Physical Review B. 101(2), 020504.
Ghazaryan, Areg, et al. “Effect of Zeeman Coupling on the Majorana Vortex Modes in Iron-Based Topological Superconductors.” Physical Review B, vol. 101, no. 2, APS, 2020, p. 020504, doi:10.1103/PhysRevB.101.020504.
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