Research Papers in Physics and Astronomy
Date of this Version
ZHANG, YANG, SHAO, WU, AND YANG. PHYSICAL REVIEW B 103, L161407 (2021). DOI: 10.1103/PhysRevB.103.L161407
Friedel oscillation is a well-known wave phenomenon which represents the oscillatory response of electron waves to imperfection. By utilizing the pseudospin-momentum locking in gapless graphene, two recent experiments demonstrate the measurement of the topological Berry phase by corresponding to the unique number of wavefront dislocations in Friedel oscillations. Here, we study the Friedel oscillations in gapped graphene, in which the pseudospin-momentum locking is broken. Unusually, the wavefront dislocations do occur like that in gapless graphene, which requires immediate verification in the current experimental condition. The number of wavefront dislocations is ascribed to the invariant pseudospin winding number in gapped and gapless graphene. This study deepens the understanding of the correspondence between topological quantity and wavefront dislocations in Friedel oscillations and implies the possibility to observe the wavefront dislocations of Friedel oscillations in intrinsic gapped two-dimensional materials, e.g., transition metal dichalcogenides.
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