Chiral superconductors from parent states with nonuniform Berry curvature: Momentum-space vortices, Bogoliubov-de Gennes topology, and thermal Hall conductivity
Abstract
We investigate chiral superconductivity emerging from parent electronic states with non-uniform Berry curvature, motivated by recent experiments in rhombohedral graphene multilayers. Using the continuum λN-model-a tunable platform with independently controllable Berry curvature profiles-we solve the full BCS gap equation on a continuum Chern band beyond the weak-coupling limit. We find that a non-uniform Berry curvature of the parent band enriches the superconducting order parameter, leading to the formation of momentum-space vortices in the gap function away from high-symmetry points. By tuning the Berry curvature profile, we identify distinct regimes associated with vortex nucleation and vortex number saturation, and show that the nucleation of momentum-space vortices tends to lower the condensation energy. We then show analytically that the parent band Chern number constrains the number of momentum-space vortices that can nucleate in the gap-independent of details of the λN-model. We also provide a gauge-invariant formulation for computing the Bogoliubov-de Gennes (BdG) Berry curvature for continuum models, and find that it is determined by a momentum-space phase current. The winding of this current around vortices in the occupied region in turn determines the BdG Chern number. Finally, we discuss how thermal Hall measurements can be used to probe the formation of momentum-space vortices. Our results highlight the crucial role of Berry curvature in shaping chiral superconductivity, and offer guiding principles for its identification in systems such as rhombohedral graphene.
Versions
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BibTeX
@misc{nir2026chiral,
title = {{Chiral superconductors from parent states with nonuniform Berry curvature: Momentum-space vortices, Bogoliubov-de Gennes topology, and thermal Hall conductivity}},
author = {L. David Le Nir and Asimpunya Mitra and Yong Baek Kim},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2605.21618},
eprint = {2605.21618},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.21618},
}
RIS
TY - UNPB
TI - Chiral superconductors from parent states with nonuniform Berry curvature: Momentum-space vortices, Bogoliubov-de Gennes topology, and thermal Hall conductivity
AU - L. David Le Nir
AU - Asimpunya Mitra
AU - Yong Baek Kim
PY - 2026
DA - 2026/08/20
PB - arXiv
DO - 10.48550/arxiv.2605.21618
UR - https://arxiv.org/abs/2605.21618
AB - We investigate chiral superconductivity emerging from parent electronic states with non-uniform Berry curvature, motivated by recent experiments in rhombohedral graphene multilayers. Using the continuum λ_N-model-a tunable platform with independently controllable Berry curvature profiles-we solve the full BCS gap equation on a continuum Chern band beyond the weak-coupling limit. We find that a non-uniform Berry curvature of the parent band enriches the superconducting order parameter, leading to the formation of momentum-space vortices in the gap function away from high-symmetry points. By tuning the Berry curvature profile, we identify distinct regimes associated with vortex nucleation and vortex number saturation, and show that the nucleation of momentum-space vortices tends to lower the condensation energy. We then show analytically that the parent band Chern number constrains the number of momentum-space vortices that can nucleate in the gap-independent of details of the λ_N-model. We also provide a gauge-invariant formulation for computing the Bogoliubov-de Gennes (BdG) Berry curvature for continuum models, and find that it is determined by a momentum-space phase current. The winding of this current around vortices in the occupied region in turn determines the BdG Chern number. Finally, we discuss how thermal Hall measurements can be used to probe the formation of momentum-space vortices. Our results highlight the crucial role of Berry curvature in shaping chiral superconductivity, and offer guiding principles for its identification in systems such as rhombohedral graphene.
ER -