摘要
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered considerable attention for their promising applications in sensors and optoelectronic devices,owing to their exceptional optical,electronic,and optoelectronic properties.However,the inherent high symmetry of TMD lattices imposes limitations on their functional versatility.Here,we present a strategy to disrupt the C_(3)rotational symmetry of monolayer WSe_(2)by fabricating a heterostructure incorporating WSe_(2)and SiP flakes.Through comprehensive experimental investigations and first-principle calculations,we elucidate that in the WSe_(2)/SiP heterostructure,excitons-both neutral and charged-emanating from WSe_(2)exhibit pronounced anisotropy,which remains robust against temperature variations.Notably,we observe an anisotropic ratio reaching up to 1.5,indicating a substantial degree of anisotropy.Furthermore,we demonstrate the tunability of exciton anisotropy through the application of a magnetic field,resulting in a significant reduction in the anisotropic ratio with increasing field strength,from 1.57 to 1.18.Remarkably,the change in heterojunction anisotropy ratio reaches 24.8%as the magnetic field increases.Our findings elucidate that the perturbation of the C_(3)rotational symmetry of the WSe_(2)monolayer arises from a non-uniform charge density distribution within the layer,exhibiting mirror symmetry.These results underscore the potential of heterostructure engineering in tailoring the properties of isotropic materials and provide a promising avenue for advancing the application of anisotropic devices across various fields.
基金
the financial support from various sources.These include the National Natural Science Foundation of China(Nos.52373311,62090035,and U19A2090)
the Youth Innovation Team of CSU(No.2019012)
the Hunan Provincial Science Fund for Distinguished Young Scholars(No.2020JJ2059)
the Hunan Province Key Research and Development Project(No.2019GK2233)
the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)
the Science and Technology Innovation Basic Research Project of Shenzhen(No.JCYJ20190806144418859)
the support of the High-Performance Complex Manufacturing Key State Lab Project,Central South University(No.ZZYJKT2020-12)
the Australian Research Council(ARC Discovery Project,DP180102976)
the support of the National Natural Science Foundation of China(Nos.92263202 and 12374020)
the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB33000000)
the National Key Research and Development Program of China(No.2020YFA0711502).
