Quantum transport in flat bands and super-metallicity

TL;DR

This paper investigates quantum transport in flat-band systems, revealing a robust super-metallic phase at the flat-band energy that is insensitive to disorder, gap size, and lattice type, with implications for graphene-based materials.

Contribution

It uncovers a super-metallic phase in flat-band systems that is resilient to various perturbations and demonstrates its universality across different lattice structures.

Findings

Super-metallic phase exists at flat-band energy despite localized states.

SM phase is robust against inelastic scattering and disorder.

Universal behavior demonstrated in Lieb lattice.

Abstract

Quantum physics in flat-band (FB) systems embodies a variety of exotic phenomenon and even counter intuitive features. The quantum transport in several graphene based compounds that exhibit a flat band and a tunable gap is investigated. Despite the localized nature of the FB states and a zero group velocity, a super-metallic (SM) phase at the FB energy is revealed. The SM phase is robust against the inelastic scattering strength and controlled only by the inter-band transitions between the FB and the dispersive bands. The SM phase appears insensitive and quasi independent of the gap amplitude and nature of the lattice (disordered or nano-patterned). The universal nature of the unconventional FB transport is illustrated with the case of electrons in the Lieb lattice.