Non-local Andreev reflection through Andreev molecular states in graphene Josephson junctions

We propose that a device composed of two vertically stacked monolayer graphene Josephson junctions can be used for Cooper pair splitting. The hybridization of the Andreev bound states of the two Josephson junction can facilitate non-local transport in this normal-superconductor hybrid structure, which we study by calculating the non-local differential conductance. Assuming that one of the graphene layers is electron and the other is hole doped, we find that the non-local Andreev reflection can dominate the differential conductance of the system. Our setup does not require the precise control of junction length, doping, or superconducting phase difference, which could be an important advantage for experimental realization.Comment: Main text + supplementar

Antisymmetric Breaking of Voltage Gauge Invariance due to Majorana States in Magnetic Topological Insulators

We theoretically discuss how Majorana bound states and Majorana chiral propagating states break voltage gauge invariance of electric transport in specific ways. While the breaking of voltage gauge invariance can be generically related to Andreev processes at interfaces, an antisymmetric conductance with respect to the point of equally split bias across a normal-superconductor-normal (NSN) junction is a more specific signal of topologically-protected Majorana modes. These electric signatures are discussed in NSN junctions made with narrow (wire-like) or wide (film-like) magnetic topological insulator slabs with a central proximitized superconducting sector

Cooper-pár szétválasztó eszközök elméleti modellezése

We investigate the possibility of Cooper pair splitting (CPS) in a four terminal, graphene based device. We use local density of states and differential conductance calculations to show that there are signs of CPS in our setup