Abstract
We use quantum Monte Carlo method to determine the magnetic and transport properties of coupled square lattice spin and fermionic planes as a model for a metal-insulator interface. Specifically, layers of Ising spins with an intralayer exchange constant interact with the electronic spins of several adjoining metallic sheets via a coupling . When the chemical potential cuts across the band center, that is, at half-filling, the Néel temperature of antiferromagnetic Ising spins is enhanced by the coupling to the metal, while in the ferromagnetic case , the metallic degrees of freedom reduce the ordering temperature. In the former case, a gap opens in the fermionic spectrum, driving insulating behavior, and the electron spins also order. This induced antiferromagnetism penetrates more weakly as the distance from the interface increases, and also exhibits a nonmonotonic dependence on . For doped lattices, an interesting charge disproportionation occurs where electrons move to the interface layer to maintain half-filling there.
8 More- Received 14 August 2014
DOI:https://doi.org/10.1103/PhysRevB.90.144418
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