Microscopic Origin and Josephson Signatures of d-Wave Superconductivity in Monolayer FeSe
Abstract
Monolayer FeSe on SrTiO3 exhibits high-temperature superconductivity with an electron-only Fermi surface, raising fundamental questions about its unconventional pairing mechanism. Motivated by recent Josephson scanning tunneling microscopy evidence for nodeless d-wave superconductivity, we investigate the microscopic role of the Fe dxy orbital using an experimentally constrained multiorbital theory. A tight-binding model fitted to quasiparticle interference and angle-resolved photoemission spectroscopy reveals substantial dxy character near the Fermi level and dominant nearest-neighbor hopping, in contrast to the conventional kinetic-frustration picture of iron-based superconductors. Both itinerant spin-fluctuation calculations and strong-coupling exchange approaches favor a robust d-wave pairing state, whose interband pairing components allow a fully gapped quasiparticle spectrum. We further establish a symmetry-based selection rule for spatial Josephson tunneling, revealing characteristic bond-centered maxima and mirror-enforced interference zeros that distinguish d-wave pairing from competing s-wave states. These symmetry-enforced nodal lines survive near Fe-site impurities, while a pronounced contrast between the d- and s-wave Josephson patterns persists around vortices despite the loss of mirror protection. Our results connect the unconventional dxy electronic structure to nodeless d-wave superconductivity and demonstrate the power of spatial Josephson interference for resolving pairing symmetry in multiorbital superconductors.
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BibTeX
@misc{mei2026microscopic,
title = {{Microscopic Origin and Josephson Signatures of $d$-Wave Superconductivity in Monolayer FeSe}},
author = {Jiong Mei and Lili Wang and Yu-Jie Sun and Kun Jiang},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.08037},
eprint = {2611.08037},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.08037},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Microscopic Origin and Josephson Signatures of d-Wave Superconductivity in Monolayer FeSe
AU - Jiong Mei
AU - Lili Wang
AU - Yu-Jie Sun
AU - Kun Jiang
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.08037
UR - https://arxiv.org/abs/2611.08037
AB - Monolayer FeSe on SrTiO_3 exhibits high-temperature superconductivity with an electron-only Fermi surface, raising fundamental questions about its unconventional pairing mechanism. Motivated by recent Josephson scanning tunneling microscopy evidence for nodeless d-wave superconductivity, we investigate the microscopic role of the Fe d_xy orbital using an experimentally constrained multiorbital theory. A tight-binding model fitted to quasiparticle interference and angle-resolved photoemission spectroscopy reveals substantial d_xy character near the Fermi level and dominant nearest-neighbor hopping, in contrast to the conventional kinetic-frustration picture of iron-based superconductors. Both itinerant spin-fluctuation calculations and strong-coupling exchange approaches favor a robust d-wave pairing state, whose interband pairing components allow a fully gapped quasiparticle spectrum. We further establish a symmetry-based selection rule for spatial Josephson tunneling, revealing characteristic bond-centered maxima and mirror-enforced interference zeros that distinguish d-wave pairing from competing s-wave states. These symmetry-enforced nodal lines survive near Fe-site impurities, while a pronounced contrast between the d- and s-wave Josephson patterns persists around vortices despite the loss of mirror protection. Our results connect the unconventional d_xy electronic structure to nodeless d-wave superconductivity and demonstrate the power of spatial Josephson interference for resolving pairing symmetry in multiorbital superconductors.
ER -