Year: 2025
Type: article
Abstract: Magic-Angle Twisted Bilayer Graphene (MATBG) shows a wide range of correlated phases which are electrostatically tunable. Despite a growing knowledge of the material, there is yet no consensus on the microscopic mechanisms driving its superconducting phase. A major obstacle to progress in this direction is that key thermodynamic properties, such as specific heat, electron-phonon coupling and superfluid stiffness, are challenging to measure due to the 2D nature of the material and its relatively low energy scales. Here, we use a gate-defined, radio frequency-biased, Josephson junction to probe the electronic dynamics of MATBG. We demonstrate evidence for two processes determining the low-frequency dynamics across the phase diagram: thermalization of electronic quasiparticles through phonon scattering and inductive response of the superconducting condensate. A phenomenological approach allows us to relate the experimentally observed dynamics to several thermodynamic properties of MATBG, including electron-phonon coupling and superfluid stiffness. Our findings support anisotropic or nodal superconductivity in MATBG and demonstrate a broadly applicable method for studying properties of 2D materials with out-of-equilibrium nanodevice dynamics. The mechanisms behind the superconducting phase in magic-angle twisted bilayer graphene (MATBG) remain debated. Here, the authors investigate radio frequency-biased Josephson junctions in MATBG, providing insights into the electron-phonon coupling and superfluid stiffness of correlated electrons.
Source: Nature Communications
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
Funders: National Science Foundation, Aspen Center for Physics, Graphene Flagship, European Commission, Ministry of Education, Culture, Sports, Science and Technology, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Fundación Bancaria Caixa d'Estalvis i Pensions de Barcelona, Horizon 2020 Framework Programme, Japan Society for the Promotion of Science, National Center of Competence in Research Quantum Science and Technology, Division of Materials Research, Core Research for Evolutional Science and Technology, H2020 European Research Council, HORIZON EUROPE European Innovation Council
Awards: G1255325603, G2442584775, G2559794857, G2595738051, G3188738659, NCCR QSIT: Quantum Science and Technology, G3803561910, G4091144171, G4162329948, G434337789, G4722835768, G4806815962, Entropy in engineered quantum systems - Mesoscopic thermodynamics of correlated quantum states, G4937468798, G4988255245, G5132640529, G5138472656, G5685278419, G5783601166, CAREER: The Fate of Topology in Disordered Three-Dimensional Materials, G6177088604, G6186848324, G6718509927, G7685134749, G7731791180, G7759009890, Programs on Critical Problems in Physics, Astrophysics and Biophysics at the Aspen Center for Physics, G7879866177, G7944295140, Toward new era of quantum electrical measurements through phase slips, G8277955443, G8334902734, G854634163, G887491987, G898758523
OpenAlex ID: W4410211899