Magnetic and metal-insulator transitions in coupled spin-fermion systems

Abstract

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. Specifically, layers of Ising spins with an intra-layer exchange constant $J$ interact with the electronic spins of several adjoining metallic sheets via a coupling $J_H$. When the chemical potential cuts across the band center, that is, at half-filling, the Néel 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 $J_H$. For doped lattices an interesting charge disproportionation occurs where electrons move to the interface layer to maintain half-filling there.

arXiv comment12 pages, 15 figures

References in corpus (19)

• Colossal Magnetoresistant Materials: The Key Role of Phase Separation
• Order-Disorder Transition in a Two-Layer Quantum Antiferromagnet
• Orbital Ordering and Unfrustrated $(\pi ,0)$ Magnetism from Degenerate Double Exchange in the Iron Pnictides
• Unified Picture for Magnetic Correlations in Iron-Based Superconductors
• Quantum Monte Carlo study of the two-dimensional fermion Hubbard Model
• Phase diagram of depleted Heisenberg model for CaV4O9
• A Monte Carlo Method for Fermion Systems Coupled with Classical Degrees of Freedom
• Anisotropy of Electrical Transport in Pnictide Superconductors Studied Using Monte Carlo Simulations of the Spin-Fermion Model
• Charge transport and magnetization profile at the interface between a correlated metal and an antiferromagnetic insulator
• Disorder-Induced Stabilization of the Pseudogap in Strongly Correlated Systems
• Control of the finite size corrections in exact diagonalization studies
• The Truncated Polynomial Expansion Monte Carlo Method for Fermion Systems Coupled to Classical Fields: A Model Independent Implementation
• Stripes and Superconductivity in Cuprates
• Evolution of superconducting correlations within magnetic-field-decoupled CuO(2) layers of La(1.905)Ba(0.095)CuO(4)
• Mapping electronic reconstruction at the metal/insulator interfaces in \ce{LaVO_3/SrVO_3} heterostructures
• Study of the One- and Two-Band Models for Colossal Magnetoresistive Manganites Using the Truncated Polynomial Expansion Method
• Kondo screening and Magnetism at Interfaces
• Distinct magnetic phase transition at the surface of an antiferromagnet
• Magnetic order in the repulsive Fermi-Hubbard model in three-dimensions and the crossover to two-dimensions

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