Phase diagram of the Kondo lattice model on the Kagome lattice

TL;DR

This paper explores the complex magnetic phases in the kagome Kondo lattice model, revealing incommensurate and non-coplanar orders driven by electron-spin interactions across different coupling regimes.

Contribution

It provides a comprehensive phase diagram of the kagome Kondo lattice model, highlighting novel magnetic orders and the effects of coupling strength and filling.

Findings

Incommensurate non-coplanar magnetic orders at weak coupling.

Persistence of complex orders near half filling at strong coupling.

Presence of non-coplanar magnetism at intermediate fillings.

Abstract

We consider the potential for novel forms of magnetism arising from the subtle interplay between electrons and spins in the under-screened kagome Kondo lattice model. At weak coupling, we show that incommensurate non-coplanar multi-wave vector magnetic orders arise at nearly all fillings and that this results from Fermi surface effects that introduces competing interactions between the spins. At strong coupling, we find that such complex order survives near half filling despite the presence of ferromagnetism at all other fillings. We show this arises due to state selection among a massive degeneracy of states at infinite coupling. Finally, we show that at intermediate filling, only commensurate orders seem to survive. But these orders still include non-coplanar magnetism. So, the mere presence of both local moments and itinerant electrons enables complex orders to form unlike any currently observed in kagome materials.