Low-dissipation edge currents without edge states

Abstract

We show that bulk free carriers in topologically trivial multi-valley insulators with non-vanishing Berry curvature give rise to low-dissipation edge currents, which are squeezed within a distance of the order of the valley diffusion length from the edge. This happens even in the absence of edge states [topological (gapless) or otherwise], and when the bulk equilibrium carrier concentration is thermally activated across the gap. Physically, the squeezed edge current arises from the spatially inhomogeneous orbital magnetization that develops from valley-density accumulation near the edge. While this current possesses neither topology nor symmetry protection and, as a result, is not immune to dissipation, in clean enough devices it can mimic low-loss ballistic transport.

References in corpus (7)

• Detecting Topological Currents in Graphene Superlattices
• Berry phase effect in anomalous thermoelectric transport
• Berry Curvature, Triangle Anomalies, and the Chiral Magnetic Effect in Fermi Liquids
• Quantum Theory of Orbital Magnetization and its Generalization to Interacting Systems
• Valley Magnetoelectricity in Single-Layer MoS2
• Edge currents shunt the insulating bulk in gapped graphene
• Marginality of bulk-edge correspondence for single-valley Hamiltonians

Cited by in corpus (10)

• Orbital Hall effect as an alternative to valley Hall effect in gapped graphene
• Orbital angular momentum of Bloch electrons: equilibrium formulation, magneto-electric phenomena, and the orbital Hall effect
• Valley Hall Effect and Non-Local Resistance in Locally Gapped Graphene
• Valley current generation using biased bilayer graphene dots
• Topological valley currents via ballistic edge modes in graphene superlattices near the primary Dirac point
• Non-conservation of the valley density and its implications for the observation of the valley Hall effect
• Nonlinear spin and orbital Edelstein effect in WTe2
• Valley Pumping via Edge States and the Nonlocal Valley Hall Effect in Two-Dimensional Semiconductors
• Three-dimensional flat bands and possible interlayer triplet pairing superconductivity in the alternating twisted NbSe${}_2$ moiré bulk
• Orbital Longitudinal Magneto-electric Coupling in Multilayer Graphene