Topological Superconductivity in Heavily Doped Single-Layer Graphene.

The existence of superconductivity (SC) appears to be established in both twisted and nontwisted graphene multilayers. However, whether their building block, single-layer graphene (SLG), can also host SC remains an open question. Earlier theoretical works predicted that SLG could become a chiral -wave superconductor driven by electronic interactions when doped to its van Hove singularity, but questions such as whether the -wave SC survives the strong band renormalizations seen in experiments, its robustness against the source of doping, or if it will occur at any reasonable critical temperature () have remained difficult to answer, in part due to uncertainties in model parameters.

Infrared Spectroscopy for Diagnosing Superlattice Minibands in Twisted Bilayer Graphene near the Magic Angle.

Twisted bilayer graphene (TBG) represents a highly tunable, strongly correlated electron system. However, understanding the single-particle band structure alone has been challenging due to a lack of spectroscopic measurements over a broad energy range. Here, we probe the band structure of TBG around the magic angle using infrared spectroscopy and reveal spectral features that originate from interband transitions.

Visualizing the topological pentagon states of a giant C metamaterial.

Systems with broken continuous symmetry in ideal lattices cannot be rectified through rearrangement or deformation. Topological metamaterials featuring nontrivial, artificially induced phase transitions have emerged as pivotal constituents for engineering these topological defects, which, until now, have mostly been experimentally realized in linear or planar configurations. Buckminster Fuller lent his name to the C ball-shaped carbon allotrope, which is not only the roundest molecule in existence but also embodies 3D topological defects.

Robust flat bands in twisted trilayer graphene moiré quasicrystals.

Moiré structures formed by twisting three layers of graphene with two independent twist angles present an ideal platform for studying correlated quantum phenomena, as an infinite set of angle pairs is predicted to exhibit flat bands. Moreover, the two mutually incommensurate moiré patterns among the twisted trilayer graphene (TTG) can form highly tunable moiré quasicrystals. This enables us to extend correlated physics in periodic moiré crystals to quasiperiodic systems.