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)cr...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.展开更多
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)+2 种基金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.)。
文摘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.
