Probing the kinetic inductance of twisted graphene superconductors

The field of strongly correlated electron systems has long captivated physicists seeking to understand how collective electron interactions give rise to exotic phenomena absent in individual particles. Over the past decade, twisted graphene-based heterostructures have emerged as a revolutionary platform for exploring strongly correlated physics. At certain 'magic' angles flat bands originate in these materials, where the kinetic energy of the charge carriers drastically reduces, and electron correlations dominate. As a result, a number of unique states such as correlated insulators and superconductors emerge, which can be tuned into simply by electrostatic doping, making it an ideal material to study correlated phenomena. It is especially interesting to investigate the novel superconducting phase, with research suggesting a pairing mechanism which cannot be explained by conventional theoretical frameworks. This thesis details my work on the electronic transport studies of magic angle twisted trilayer graphene (MATTG) heterostructures by designing experiments to probe fundamental properties, such as the kinetic inductance and coherence length, of this superconducting phase. We first investigate superconductivity in this material by integrating it as the weak link in a superconducting quantum interference device (SQUID). By studying how the phase winds across the weak link, we determine the kinetic inductance of MATTG in its intrinsic superconducting state. We find that MATTG has a large kinetic inductance, electrostatically tunable by nearly an order of magnitude, and also extract a coherence length larger than that reported for this material previously in literature. Finally, we explore high frequency superconducting circuits to measure the kinetic inductance of MATTG, by characterizing microwave resonators with different superconducting materials, tailored towards realising MATTG integrated microwave resonators.