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Abstract
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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.
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