The stacking of twisted two-dimensional(2D)layered materials has led to the creation of moirésuperlattices,which have become a new platform for the study of quantum optics.The strong coupling of moirésuperla...The stacking of twisted two-dimensional(2D)layered materials has led to the creation of moirésuperlattices,which have become a new platform for the study of quantum optics.The strong coupling of moirésuperlattices can result in flat minibands that boost electronic interactions and generate interesting strongly correlated states,including unconventional superconductivity,Mott insulating states,and moiréexcitons.However,the impact of adjusting and localizing moiréexcitons in Van der Waals heterostructures has yet to be explored experimentally.Here,we present experimental evidence of the localization-enhanced moiréexcitons in the twisted WSe_(2)/WS_(2)/WSe_(2)heterotrilayer with type-II band alignments.At low temperatures,we observed multiple excitons splitting in the twisted WSe_(2)/WS_(2)/WSe_(2)heterotrilayer,which is manifested as multiple sharp emission lines,in stark contrast to the moiréexcitonic behavior of the twisted WSe_(2)/WS_(2)heterobilayer(which has a linewidth 4 times wider).This is due to the enhancement of the two moirépotentials in the twisted heterotrilayer,enabling highly localized moiréexcitons at the interface.The confinement effect of moirépotential on moiréexcitons is further demonstrated by changes in temperature,laser power,and valley polarization.Our findings offer a new approach for localizing moiréexcitons in twist-angle heterostructures,which has the potential for the development of coherent quantum light emitters.展开更多
基金The authors express their gratitude to various organizations for their support in this research,including the National Natural Science Foundation of China(Grant No.61775241)the Hunan province key research and development project(Grant No.2019GK2233)+8 种基金the Hunan Provincial Science Fund for Distinguished Young Scholars(Grant No.2020JJ2059)the Youth Innovation Team(Grant No.2019012)of CSU.Additionally,they acknowledge the Science and Technology Innovation Basic Research Project of Shenzhen(Grant No.JCYJ20190806144418859)the National Natural Science Foundation of China(Nos.62090035 and U19A2090)the Key Program of Science and Technology Department of Hunan Province(2019XK2001,2020XK2001)The authors also thank the High-Performance Complex Manufacturing Key State Lab Project of Central South University(Grant No.ZZYJKT2020-12)for their support.Z.W.Lacknowledges the support from the Australian Research Council(ARC Discovery Project,DP180102976)C.T.W.is grateful for the support from the National Natural Science Foundation of China(Grant No.11974387)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)H.H.Z.acknowledges the support from the Postdoctoral Science Foundation of China(2022M713546).Finally,the authors recognize the Beijing Super Cloud Computing Center(BSCC)for providing HPC resources,which have greatly contributed to the results reported in this paper.
文摘The stacking of twisted two-dimensional(2D)layered materials has led to the creation of moirésuperlattices,which have become a new platform for the study of quantum optics.The strong coupling of moirésuperlattices can result in flat minibands that boost electronic interactions and generate interesting strongly correlated states,including unconventional superconductivity,Mott insulating states,and moiréexcitons.However,the impact of adjusting and localizing moiréexcitons in Van der Waals heterostructures has yet to be explored experimentally.Here,we present experimental evidence of the localization-enhanced moiréexcitons in the twisted WSe_(2)/WS_(2)/WSe_(2)heterotrilayer with type-II band alignments.At low temperatures,we observed multiple excitons splitting in the twisted WSe_(2)/WS_(2)/WSe_(2)heterotrilayer,which is manifested as multiple sharp emission lines,in stark contrast to the moiréexcitonic behavior of the twisted WSe_(2)/WS_(2)heterobilayer(which has a linewidth 4 times wider).This is due to the enhancement of the two moirépotentials in the twisted heterotrilayer,enabling highly localized moiréexcitons at the interface.The confinement effect of moirépotential on moiréexcitons is further demonstrated by changes in temperature,laser power,and valley polarization.Our findings offer a new approach for localizing moiréexcitons in twist-angle heterostructures,which has the potential for the development of coherent quantum light emitters.
