Berry - phase effect on reflection amplitude in bilayer graphene with potential step

Submitted for the MAR10 Meeting of The American Physical Society Berry-phase effect on reflection amplitude in bilayer graphene with potential step SUNGHUN PARK, H.-S. SIM, KAIST — We theoretically study the phase of the reflection amplitude of an electron at a lateral potential step in Bernal-stacked bilayer graphene [1]. The phase shows an anomalous jump of π, as the electron incidence angle (relative to the normal direction to the step) varies to pass ±π/4. The jump is attributed to the Berry phase associated with the pseudospin-1/2 of the electron. This Berry-phase effect is robust against the bandgap opening due to the external gates generating the step, and can be observed in an interferometry setup. [1] Sunghun Park and H.-S. Sim, Phys. Rev. Lett. 103, 196802 (2009).