We consider the Cauchy problem for the two-dimensional massless Dirac equation in graphene with a constant electric field. It is assumed that at the initial time, a localized wave function describes quasi-electrons with momenta lying in the right half-plane. We describe the effect based on the phenomenon of changing the multiplicity of terms (characteristics), which leads to Klein tunneling and consists in the fact that, after some time, a hole component appears in addition to the wave function for the electron component. The components move in opposite directions, and the hole component localizes near a moving point.
Bogaevskii et al. (Sun,) studied this question.