M. Oliva-Leyva, G. G. Naumis
The behavior of electrons in strained graphene is usually described using effective pseudomagnetic fields in a Dirac equation. Recently, such description has been completed by the explicit inclusion of lattice deformations, although yet it is not clear the physical interpretation of the modified resulting equations, or if they really produce new pseudomagnetic fields. Here we consider the particular case of a spatially constant strain. Our results indicate that lattice corrections are easily understood using a strained reciprocal space, in which the whole energy dispersion is simply shifted and deformed by the space shrinking. This leads to a directional dependent Fermi velocity without producing pseudomagnetic fields. The corrections due to atomic wavefunction overlap changes tend to compensate such effects. Also, the analytical expressions for the shift of the Dirac points as well as the corresponding Dirac equation are found. In view of the former results, we discuss the range of applicability of the usual approach of considering pseudomagnetic fields in a Dirac equation derived from the old Dirac points of the unstrained lattice. Such considerations are important if a comparison is desired with experiments or numerical simulations.
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http://arxiv.org/abs/1304.6682
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