Is There Any Klein Paradox? Look at Graphene!

It is demonstrated that both transmission and reflection coefficients associated to the Klein paradox at a step barrier are positive and less than unity, so that the particle-antiparticle pair creation mechanism commonly linked to this phenomenon is unnecessary. An experimental configuration using a graphene sheet is proposed to decide between the results obtained in this paper and the common Klein paradox theory, which imply negative transmission and higher-than-unity reflection coefficients. Graphene is a solid-state testing ground for quantum electrodynamics phenomena involving massless Dirac fermions