Exactly solvable 2D topological Kondo lattice model

TL;DR

This paper introduces an exactly solvable 2D topological Kondo lattice model on a honeycomb lattice, revealing hybridization-induced insulating states and chiral edge modes through Majorana fermion analysis.

Contribution

It presents a novel exactly solvable model combining Kitaev interactions with spinless fermions, providing insights into fermion-moment hybridization and topological phases in Kondo lattices.

Findings

Kondo hybridization gap leads to insulator and spin insulator states

System exhibits chiral gapless edge states in topological phases

Rich ground-state phase diagram with various phases

Abstract

A spin-$\frac{1}{2}$ Kitaev sublattice interacting with a subsystem of spinless fermions is studied on a honeycomb lattice when the fermion band is half filled. The model Hamiltonian describes a topological Kondo lattice with the Kitaev interaction, it is solved exactly by reduction to free Majorana fermions in a static $\mathbb{Z}_2$ gauge field. An yet unsolved problem of a hybridization of fermions and local moments in the Kondo lattice at low temperatures is solved in the framework of the model proposed. The Kondo hybridization gap is opened and the system is fixed in insulator and spin insulator states, due to a spin-fermion nature of the gap. We will show that the hybridization between local moments and itinerant fermions should be understand as hybridization between corresponding Majorana fermions of the spin and charge sectors. The RKKI interaction between local moments is not realized in the model, a system demonstrates a `quasi Kondo' scenario of behavior with realization chiral gapless edge states in topological nontrivial phases. The ground-state phase diagram of the interacting subsystems calculated in the parameter space is rich.