Junctions and Superconducting Symmetry in Twisted Bilayer Graphene
Héctor Sainz-Cruz, Pierre A. Pantaleón, Võ Tiến Phong, Alejandro Jimeno‐Pozo, F. Guinea
Abstract
Junctions provide a wealth of information on the symmetry of the order parameter of superconductors. We analyze junctions between a scanning tunneling microscope (STM) tip and superconducting twisted bilayer graphene (TBG) and TBG Josephson junctions (JJs). We compare superconducting phases that are even or odd under valley exchange (s- or f-wave). The critical current in mixed (s and f) JJs strongly depends on the angle between the junction and the lattice. In STM-TBG junctions, due to Andreev reflection, the f-wave leads to a prominent peak in subgap conductance, as seen in experiments.
Topics & Concepts
Condensed matter physicsSuperconductivityAndreev reflectionBilayer grapheneJosephson effectScanning tunneling microscopeQuantum tunnellingGrapheneReflection symmetryConductanceBilayerPhysicsHexagonal latticeSymmetry (geometry)Quantum mechanicsChemistryAntiferromagnetismMembraneGeometryMathematicsBiochemistryPhysics of Superconductivity and MagnetismGraphene research and applicationsQuantum and electron transport phenomena