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arXiv · 2508.09551

Twist-angle tunable Josephson junctions in three-dimensional superconductors

Tenta Tani·Takuto Kawakami·Mikito Koshino
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Abstract

We theoretically investigate the superconducting phase and perpendicular Josephson supercurrent in twisted three-dimensional (3D) superconductors, where two layered 3D materials are stacked with a relative twist. We formulate the Bogoliubov-de Gennes Hamiltonian and develop a self-consistent method to calculate the superconducting order parameter and the resulting supercurrent. Applying this framework to a toy model with Fermi surfaces located near the Brillouin zone corners, we demonstrate a phase discontinuity at the twisted interface, indicating that a Josephson junction is formed purely by the twist. Our calculations reveal that the interface supports a finite critical current even when the Fermi surfaces of the two superconductors are completely separated, unlike in the case of a twisted normal-metal interface. We further show that the critical current can be effectively controlled by the twist angle, transitioning from a high-transparency regime at small angles to a low-transparency regime at larger angles.

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Tenta Tani, Takuto Kawakami, Mikito Koshino. 2026-01-13. Twist-angle tunable Josephson junctions in three-dimensional superconductors. https://doi.org/10.1103/p3vk-nmp7

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