Andreev reflection in bilayer graphene: Crossover from retro-reflection to specular reflection

Andreev reflection in graphene is special since it can be of two types- retro or specular. Bilayer graphene (BLG) is a better candidate to observe the crossover from retro to specular since charge density fluctuations across the sample are much lower. We propose a scheme to observe the features of specular Andreev reflection in normal metal (NM)-superconductor (SC) junction on BLG more clearly. Our scheme involves applying a magnetic field to the NM side of the NM-SC junction on BLG. We calculate conductance as a function of chemical potential and bias within the superconducting gap. From the conductance spectrum, we identify the regions of specular- and retro- type Andreev reflection.