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arXiv · 2308.10530

Displacement-field-tunable superconductivity in an inversion-symmetric twisted van der Waals heterostructure

Harley D. Scammell·Mathias S. Scheurer
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Abstract

We investigate the superconducting properties of inversion-symmetric twisted trilayer graphene by considering different parent states, including spin-singlet, triplet, and SO(4) degenerate states, with or without nodal points. By placing transition metal dichalcogenide layers above and below twisted trilayer graphene, spin-orbit coupling is induced in TTLG and, due to inversion symmetry, the spin-orbit coupling does not spin-split the bands. The application of a displacement field ($D_0$) breaks the inversion symmetry and creates spin-splitting. We analyze the evolution of the superconducting order parameters in response to the combined spin-orbit coupling and $D_0$-induced spin-splitting. Utilizing symmetry analysis combined with both a direct numerical evaluation and a complementary analytical study of the gap equation, we provide a comprehensive understanding of the influence of spin-orbit coupling and $D_0$ on superconductivity. These results contribute to a better understanding of the superconducting order in twisted trilayer graphene.

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Harley D. Scammell, Mathias S. Scheurer. 2023-08-21. Displacement-field-tunable superconductivity in an inversion-symmetric twisted van der Waals heterostructure. https://doi.org/10.1103/physrevb.109.035159

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