Resolving intervalley gaps and many-body resonances in moiré superconductors
Summary
This Nature paper reports high-resolution scanning tunnelling microscopy (STM) and point-contact spectroscopy on magic-angle multilayer/twisted graphene devices (MATTG/MATBG). The authors identify two distinct spectral gaps — an “inner” and an “outer” gap — tied to intervalley-coherent ordering (Kekulé/IKS-type orders) and superconducting behaviour. They also observe sharp, zero-bias many-body resonances (Kondo-like) that coexist with flat-band features, and show how these features evolve with temperature, gating and tip–sample coupling. The experimental data are supported by dynamical mean-field theory (DMFT) and iterative perturbation-theory modelling that favour a heavy-fermion / many-body resonance interpretation of some observations. Data and raw figures are available on Zenodo (https://doi.org/10.5281/zenodo.17884628).
Key Points
- Two distinct gaps (inner and outer) are resolved in moiré graphene spectroscopies; their size and coexistence vary with local twist angle and filling.
- Intervalley-coherent (IKS / Kekulé) real-space order is imaged and shown to correlate with the inner gap and local spectroscopy.
- Zero-bias many-body resonances — consistent with Kondo-like physics or emergent local moments hybridising with flat bands — are repeatedly observed and track temperature and doping.
- Point-contact Andreev reflection signatures indicate superconducting behaviour that can coexist with the intervalley gaps and resonances, depending on local conditions and tip coupling.
- Theory (DMFT and iterative perturbation calculations) supports an interpretation in which heavy-fermion-like emergent bands and many-body screening play a role in the observed spectroscopic features.
- Raw data and code supporting the work are available on reasonable request and key datasets are archived on Zenodo.
Content summary
The study combines atomic-scale STM mapping, gate-dependent tunnelling spectroscopy and point-contact spectroscopy across multiple magic-angle twisted graphene devices. The authors map real-space Kekulé/IKS patterns and show a close relationship between local bond-order patterns and the appearance of the inner spectral gap. They track temperature dependence of the inner gap and the zero-bias resonance, demonstrating that the resonance weakens with temperature in a manner reminiscent of Kondo physics. Tip–sample distance and tip-induced local doping shift some spectral features (notably the outer gap) while leaving others relatively robust. Theoretical calculations (DMFT, iterative perturbation theory) reproduce aspects of the spectral function, supporting a picture where interaction-driven heavy quasiparticles and local-moment screening coexist with flat-band superconductivity in moiré graphene.
The paper contains extensive extended-data figures documenting spatial maps, bias- and gate-dependent spectroscopy, temperature sweeps, tip-height dependence, and comparisons across devices with slightly different twist angles. The authors provide full acknowledgements, author contributions and declare no competing interests.
Context and relevance
This work sits at the intersection of two hot topics in quantum materials: moiré flat-band physics and many-body emergent phenomena (heavy fermions / Kondo-like resonances). By resolving intervalley-coherent order alongside superconducting and Kondo-like signatures at the local scale, the paper advances our understanding of how competing orders and local correlations shape superconductivity in moiré graphene systems. The findings are relevant to experimentalists working with STM/PCS on 2D moiré materials, and to theorists modelling interaction-driven band renormalisation and emergent local moments. It also informs efforts to engineer correlated phases in twisted multilayer graphene and related heterostructures.
Why should I read this?
Short version: if you care about how flat bands, local moments and superconductivity actually show up in the microscope — not just on paper — this paper is gold. The authors did the tedious mapping, temperature and tip-control work so you don’t have to, and they tie the messy local real-space picture (Kekulé/IKS order, tip doping effects) to clear spectroscopic fingerprints. In plain terms: it’s where experiment and many-body theory meet and disagree constructively — read it if you want to understand what’s real versus what’s ideal in moiré superconductors.
Author take
Punchy: this is a big experimental step. The combination of local imaging, gating, point-contact Andreev probes and careful modelling gives a convincing case that intervalley coherence, many-body resonances and superconductivity are intertwined in magic-angle moiré graphene. If you’re working on correlated 2D materials or trying to pin down pairing mechanisms in flat-band superconductors, the details here matter — read the full paper.
Source
Article Date: 04 February 2026
Article URL: https://www.nature.com/articles/s41586-025-10067-1
Raw data: https://doi.org/10.5281/zenodo.17884628