Exactly solvable 2D topological Kondo lattice model

G.V. Kurdyumov Institute for Metal Physics, N.A.S. of Ukraine - 36 Vernadsky Boulevard, 03142 Kiev, Ukraine

Received: 8 December 2014
Accepted: 9 February 2015

Abstract

A spin- 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 gauge field. A 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 proposed model. The Kondo hybridization gap is opened and the system is fixed in insulator and spin insulator states, due to the spin-fermion nature of the gap. We will show that the hybridization between local moments and itinerant fermions should be understood 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.