Magnetic and metal-insulator transitions in coupled spin-fermion systems
- Pennsylvania State Univ., University Park, PA (United States). Dept of Physics; Univ. of California, Davis, CA (United States). Dept. of Physics
- Univ. Federal do Rio de Janeiro, Rio de Janeiro (Brazil)
- Univ. of California, Davis, CA (United States). Dept. of Physics
Here, we use quantum Monte Carlo to determine the magnetic and transport properties of coupled square lattice spin and fermionic planes as a model for a metal-insulator interface. Speci cally, layers of Ising spins with an intra-layer exchange constant J interact with the electronic spins of several adjoining metallic sheets via a coupling JH. Furthermore, when the chemical potential cuts across the band center, that is, at half- filling, the Neel temperature of antiferromagnetic (J > 0) Ising spins is enhanced by the coupling to the metal, while in the ferromagnetic case (J < 0) 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 non-monotonic dependence on JH. Lastly, for doped lattices an interesting charge disproportionation occurs where electrons move to the interface layer to maintain half- filling there.
- Research Organization:
- Univ. of California, Davis, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- NA0001842; NA0001842-0
- OSTI ID:
- 1344112
- Alternate ID(s):
- OSTI ID: 1180752; OSTI ID: 1344121
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 90, Issue 14; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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