Exotic magnetic phases in an Ising-spin Kondo lattice model on a kagome lattice

Magnetic and electronic states of an Ising-spin Kondo lattice model on a kagome lattice are investigated by a Monte Carlo simulation. In addition to the conventional ferromagnetic and ferrimagnetic orders, we show that this model exhibits several thermally-induced phases, such as partially disordered, Kosteritz-Thouless-like, and loop-liquid states. In the partially disordered state, we show that the magnetic transition is associated with the charge-gap formation. We find that the density of state shows characteristic peaks reflecting the underlying spin texture. In the loop-liquid state, we also find a peak in a different manner in the density of states as well as in the optical conductivity. This is a consequence of the formation of closed loops of the same spin sites in the loop-liquid state. Our results elucidates the peculiar cooperation between thermal fluctuations and the spin-charge interplay in this frustrated itinerant electron system.