Abstract

Graphene-based Josephson junctions provide a platform for investigating phase coherent transport in graphene, a strictly two-dimensional system, where the Josephson Effect requires both phase coherence and time reversal symmetry [1]. Graphene possesses unique physical properties such as low-energy linear dispersion relation, vanishing density of states at the Dirac point and tunable carrier density (and type), making it relatively straightforward to probe the Josephson phase diagram as well as interesting to study the transport in a 2D system of relativistic particles. Recently, the field of graphene-superconductor hybrid structures has attracted much attention due to the relevance of Dirac point physics to topological insulators, applications of graphene-based junctions to superconducting qubits, and the presence of specular Andreev reflection at zero doping in the ballistic regime [2] (which is also related to the realization of electron optics). In this workshop, I will discuss transport measurements taken from our first batch of graphene Josephson junctions fabricated on Si/SiO2 substrate, where the graphene flakes are contacted by superconducting niobium nitride electrodes with a critical temperature of approximately 6K. In addition, I will talk about potential future work for our research and how we can achieve a supercurrent through graphene.

1. Heersche, H. et al., Manifestations of phase coherent transport in graphene, Eur. Phys. J. Special Topics, 148, 27-37 (2007) 2. Beenakker, C. W., Specular Andreev Reflection in Graphene, Phys. Rev. Lett., 97, 067007 (2006) 3. Doh, Y. J. et al., Quantum Interference Effects in InAs Semiconductor Nanowires, Journal of Korean Physical Society, 54, 135-139 (2009)