4 research outputs found
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
Conductance asymmetry in proximitized magnetic topological insulator junctions with Majorana modes
We theoretically discuss electronic transport via Majorana states in magnetic topological insulator-superconductor junctions with an asymmetric split of the applied bias voltage. We study normal-superconductor-normal (NSN) junctions made of narrow (wire-like) or wide (film-like) magnetic topological insulator slabs with a central proximitized superconducting sector. The occurrence of charge non-conserving Andreev processes entails a nonzero conductance related to an electric current flowing to ground from the proximitized sector of the NSN junction. We show that topologically-protected Majorana modes require an antisymmetry of this conductance with respect to the point of equally split bias voltage across the junction.This project is financially supported by the QuantERA grant MAGMA, by the National Research Fund Luxembourg under the grant INTER/QUANTERA21/16447820/MAGMA, by the German Research Foundation under grant 491798118, by MCIN/AEI/10.13039/501100011033 under project PCI2022-132927, and by the European Union NextGenerationEU/PRTR. L.S. acknowledges support from Grants No. PID2020-117347GB-I00 funded by MCIN/AEI/10.13039/501100011033 and No. PDR2020-12 funded by GOIB. K.M. acknowledges the financial support by the Bavarian Ministry of Economic Affairs, Regional Development and Energy within Bavaria’s High-Tech Agenda Project ”Bausteine f¨ur das Quantencomputing auf Basis topologischer Materialien mit experimentellen und theoretischen Ans¨atzen” (grant allocation no. 07 02/686 58/1/21 1/22 2/23).N