Evanescent-mode-assisted Klein tunneling in dual-gated bilayer graphene

Abstract: We theoretically investigate the electron tunneling in dual-gated bilayer graphene-based $n/p$ junctions. It is shown that a band gap is introduced by tuning the gate voltage, which modifies the pseudospin polarization and breaks anti-Klein tunneling at normal incidence. Specifically, when the pseudospin polarization vectors for the propagating and evanescent wave modes on the left and right regions of the junction are orthogonal, a revival of Klein tunneling is achieved. The Berry phase associated with Klein tunneling in dual-gated bilayer graphene is not limited to $\pi$ but varies with the junction parameters. Furthermore, the Klein tunneling is accompanied by a $\pi$ jump in the reflection phase around the normal incidence.