Continuous and reversible tuning of the disorder-driven superconductor-insulator transition in bilayer graphene

Abstract

The influence of static disorder on a quantum phase transition (QPT) is a fundamental issue in condensed matter physics. As a prototypical example of a disorder-tuned QPT, the superconductor-insulator transition (SIT) has been investigated intensively over the past three decades, but as yet without a general consensus on its nature. A key element is good control of disorder. Here, we present an experimental study of the SIT based on precise in-situ tuning of disorder in dual-gated bilayer graphene proximity-coupled to two superconducting electrodes through electrical and reversible control of the band gap and the charge carrier density. In the presence of a static disorder potential, Andreev-paired carriers formed close to the Fermi level in bilayer graphene constitute a randomly distributed network of proximity-induced superconducting puddles. The landscape of the network was easily tuned by electrical gating to induce percolative clusters at the onset of superconductivity. This is evidenced by scaling behavior consistent with the classical percolation in transport measurements. At lower temperatures, the solely electrical tuning of the disorder-induced landscape enables us to observe, for the first time, a crossover from classical to quantum percolation in a single device, which elucidates how thermal dephasing engages in separating the two regimes.

43 pages, 16 figures, submitted

References in corpus (16)

• Electric Field Effect in Atomically Thin Carbon Films
• Asymmetry gap in the electronic band structure of bilayer graphene
• Carrier transport in 2D graphene layers
• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Bipolar supercurrent in graphene
• Transport measurements across a tunable potential barrier in graphene
• Localization of preformed Cooper-pairs in disordered superconductors
• Nature of the superconductor-insulator transition in disordered superconductors
• Determination of the electronic structure of bilayer graphene from infrared spectroscopy results
• The Higgs Mode in Disordered Superconductors Close to a Quantum Phase Transition
• Electrical Control of the Superconducting-to-Insulating Transition in Graphene/Metal Hybrids
• Density inhomogeneity driven percolation metal-insulator transition and dimensional crossover in graphene nanoribbons
• Transport and percolation in a low-density high-mobility two-dimensional hole system
• Electron-phonon mediated heat flow in disordered graphene
• Phonon bottleneck in graphene-based Josephson junctions at millikelvin temperatures
• Superconductor-insulator quantum phase transition

Cited by in corpus (5)

• Proximity coupling in superconductor-graphene heterostructures
• Short Ballistic Josephson Coupling in Planar Graphene Junctions with Inhomogeneous Carrier Doping
• Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators
• Characterization of a graphene-hBN superlattice field effect transistor
• Insulator-pseudogap crossover in the Lieb lattice