Realization of correlated and topological electronic states in crystalline graphene

Electron-electron interactions can be significant in graphene with an ABC-stacking sequence. By developing innovative experimental techniques, we successfully fabricated high-quality ABC-stacked multilayer graphene and observed a correlated insulating state at charge neutrality, beginning with ABCA-tetralayer. Furthermore, by introducing proximity-induced spin-orbit coupling, at the charge neutrality point of ABCA-tetralayer, we achieved a topological Chern insulator with a layer-number-dependent Chern number of four.

The work at SJTU was supported by National Key Research Program of China (Grant Nos. 2021YFA1400100 and 2020YFA0309000), NSF of China (Grant Nos. 12350005 and 12174248), Shanghai Science and Technology Innovation Action Plan (Grant No. 24LZ1401100) and the Yangyang Development Fund.

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