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Dynamical Strain‐Induced Charge Pumping in Monolayer Graphene
Author(s) -
Farajollahpour Tohid,
Phirouznia Arash
Publication year - 2018
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201700284
Subject(s) - berry connection and curvature , condensed matter physics , graphene , brillouin zone , polarization (electrochemistry) , population , charge (physics) , physics , magnetic field , curvature , context (archaeology) , geometry , geometric phase , quantum mechanics , chemistry , geology , mathematics , paleontology , demography , sociology
Emergence of high pseudo‐magnetic field as a result of mechanical deformations is one of the intriguing characteristics of the graphene honeycomb structure. For a time‐dependent nonuniform strain and in the context of Berry curvature approach, the topological charge pumping is studied theoretically. Calculations have been performed in time–momentum parametric space. Within the Berry curvature approach, it has been revealed that time‐dependent deformations result in nonzero valley‐dependent charge pumping in the gapped graphene when there is a population imbalance between the valleys. This indicates that the valley polarization can be measured by the amount of topological charge pumping in the system. Results also show that the strain can remove the valley degeneracy at nonzero Fermi energies. Therefore, population imbalance or valley polarization can be realized as a result of the external strain. Strain has been considered as gauge field that couples oppositely with two valleys of the Brillouin zone.