Quantum superwires: dynamically confined electrons in superlattices*

Flat bands in Moiré and other superlattice structures are associated with spectacular phenomenology, varying from high-temperature superconductivity to the emergence of topological states of matter. Here, however, we connect the physics of flat bands belonging to high Brillouin zones to recently discovered "superwires", which refer to the dynamical quasi-one-dimensional localization of electrons within static two-dimensional superlattices. In contrast to a similar phenomenon occurring in photonic band gap materials, these localized electrons have wavelengths notably smaller than the superlattice constant, yet larger than the atomic length scale. Furthermore, we analyze the dynamical confined electrons in terms of a paraxial approximation, revealing that perfect electronic wires can form under specific resonance conditions. We find that phonon-electron scattering within the flat band regime is strongly suppressed, which further raises an alluring possibility of zero-resistivity wires guiding electron flow through the lattice. Together with their robustness and tuneability, superwires can thus provide an alternative way to control electron transport in nanoscale structure with high fidelity.