Fractional second-order topological insulator from a three-dimensional coupled-wires construction

Abstract

We construct a three-dimensional second-order topological insulator with gapless helical hinge states from an array of weakly tunnel-coupled Rashba nanowires. For suitably chosen interwire tunnelings, we demonstrate that the system has a fully gapped bulk as well as fully gapped surfaces, but hosts a Kramers pair of gapless helical hinge states propagating along a path of hinges that is determined by the hierarchy of interwire tunnelings and the boundary termination of the system. Furthermore, the coupled-wires approach allows us to incorporate electron-electron interactions into our description. At suitable filling factors of the individual wires, we show that sufficiently strong electron-electron interactions can drive the system into a fractional second-order topological insulator phase with hinge states carrying only a fraction $e/p$ of the electronic charge $e$ for an odd integer $p$.

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Cited by in corpus (6)

• Fractional Spin Quantum Hall Effect in Weakly Coupled Spin Chain Arrays
• Dimensional reduction of the Luttinger-Ward functional for spin-degenerate $D$-dimensional electron gases
• RKKY interaction in helical higher-order topological insulators
• Perfectly localized Majorana corner modes in fermionic lattices
• Fractional chiral second-order topological insulator from a three-dimensional array of coupled wires
• Coupled-wire construction of non-Abelian higher-order topological phases