▎ 摘　　要

It is demonstrated that both transmission and reflection coefficients associated with 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 not necessary. Because graphene is a solid-state testing ground for quantum electrodynamics phenomena involving massless Dirac fermions, we suggest that the transport characteristic through a p-n graphene junction can decide between the results obtained in this paper and the common Klein paradox theory, which imply negative transmission and higher-than-unity reflection coefficients. Recent experimental evidence supports our findings.