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arXiv · 2407.16044

Unconventional superconductivity in magic-strain graphene superlattices

Qingxiang Ji·Bohan Li·Johan Christensen·Changguo Wang·Muamer Kadic
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Abstract

Extensive investigations on the Moir\'e magic-angle have been conducted in twisted bilayer graphene, unlocking the mystery of unconventional superconductivity and insulating states. In analog to magic angle, here we demonstrate the new concept of magic-strain in graphene systems by judiciously tailoring mechanical relaxation (stretch and compression) which is easier to implement in practice. We elucidate the interplay of strain-induced effects and delve into the resulting unconventional superconductivity or semimetal-insulator transition in relaxation-strained graphene, going beyond the traditional twisting approach. Our findings reveal how relaxation strain can trigger superconducting transitions (with an ultra-flat band at the Fermi level) or the semimetal-insulator transition (with a gap opening at the $K$ point of $0.39\rm{~eV}$) in both monolayer and bilayer graphene. These discoveries open up a new branch for correlated phenomena and provide deeper insights into the underlying physics of superconductors, which positions graphene as a highly tunable platform for novel electronic applications.

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Qingxiang Ji, Bohan Li, Johan Christensen, Changguo Wang, Muamer Kadic. 2024-07-22. Unconventional superconductivity in magic-strain graphene superlattices. https://arxiv.org/abs/2407.16044

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