摘要
Skyrmions—topological spin/pseudospin textures—are natural charge excitations of quantum Hall(QH)ferromagnets.In a WSe_(2)-encapsulated bilayer graphene(BLG)heterostructure,we tune the valley-only Landau level(LL)crossings atν=±3 with an out-of-plane displacement field(D field)and use them as a platform to probe valley excitations.Activation gap measurements reveal a finite gap at degeneracy that rises sharply with D field near the crossing and exceeds the single-particle valley susceptibility,suggesting valley-skyrmion charge excitations.We quantify the skyrmion size and elucidate the mechanism governing its magnetic-field dependence.Similar behavior appears at valley-orbital and valley-spin entangled crossings(ν=±2 andν=±1,respectively).These results suggest controlled valley-skyrmion formation in BLG and open a route to engineering interacting multicomponent QH ferromagnets with tunable spin/pseudospin textures.
基金
Peking University was supported by the National Key Research and Development Program of China(Grant No.2021YFA1401900)
the National Natural Science Foundation of China(NSFC)(Grant No.12141001)
Zhejiang University was supported by the NSFC(Grant Nos.12374047 and U23A2076)
the Fundamental Research Funds for the Central Universities(Grant No.226-2025-00118)
the National Key Research and Development Program of China(Grant No.2021YFA1401902 for Z.L.)。
