A Haldane phase in a one-dimensional topological Kondo insulator

LOBOS, ALEJANDRO M.; MEZIO, ALEJANDRO; GAZZA, CLAUDIO J.; DOBRY, ARIEL O.

Clear Water Bay, Kowloon Hong Kong, CN

Conferencia; Topological and Correlated Gordon Research Conference "Topological Phases: From Fundamentals to New Discoveries"; 2017

The Gordon Research Conferences

A complete topological classification of gapped phases of noninteracting fermions has been achieved in past years, and an interesting open question today is how to classify strongly interacting systems. In this sense, a new class of topological material with strong correlations are the so-called ?topological Kondo insulators?, where a Kondo insulator becomes topologically-ordered due to the different parity of hybridised f- and d- orbital bands and strong spin-orbit coupling. In this work, we use the density-matrix renormalization group (DMRG) method to calculate the properties of a recently proposed model for a topological Kondo insulator in one dimension, the p-wave Kondo-Heisenberg model (p-KHM) [1]. This model has an unusual nonlocal Kondo-type interaction that couples localised spins with the ?p-wave? spin density of conduction electrons. Based on the analysis of the charge- and spin-excitations gaps, the string order parameter, and the spin profile in the ground state, we show that the system realises an unexpected Haldane phase (a symmetry-protected topological phase related to the antiferromagnetic spin-1 chain) and hosts topologically protected spin-1/2 edge states. We also propose that the p-KHM could be experimentally implemented in p-band optical lattices loaded with ultracold Fermi gases.[1] Alexandrov and Coleman, Phys. Rev. B 90, 115147 (2014)