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arXiv · 2607.27355

Flat-band formation and chiral superconductivity in driven topological insulators

Suman Jyoti De·Leo Goutte·Kartiek Agarwal·T. Pereg-Barnea
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Abstract

We demonstrate that circularly polarized light can be used to Floquet-engineer nearly flat or Mexican-hat like electronic bands on the surface of three-dimensional topological insulators (3D TIs), which under suitable conditions, can support topological superconductivity via purely repulsive Coulomb interactions. The driving acts not merely by gapping out the Dirac cone on the surface of the 3D TI, but can be used to diminish, and even flip in sign, the intrinsic curvature of the surface state dispersion away from the Dirac point. Using parameters for canonical 3D TIs, we find that the flat band limit is attained for reasonable electric fields and the bands realized by changing the strength of the driving field have a similar energetic and spatial profile to those obtained in rhombohedral graphene under varying displacement field, where the case for superconductivity with purely repulsive interactions has recently been made. We find that, with the aid of appropriately placed screening metallic gate, one can obtain $T_c \sim 7 $K in this setup while avoiding Wigner crystallization for low electron densities in the range of $10^{11}-10^{12}/\text{cm}^2$.

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Suman Jyoti De, Leo Goutte, Kartiek Agarwal, T. Pereg-Barnea. 2026-07-29. Flat-band formation and chiral superconductivity in driven topological insulators. https://arxiv.org/abs/2607.27355

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