Long-range magnetic order and the Darwin Lagrangian

Long-range magnetic order and the darwin lagrangian

We simulate a finite system of N confined electrons with inclusion of the Darwin magnetic interaction in two and three dimensions. The lowest-energy states are located using the steepest descent quenching adapted for velocity dependent potentials. Below a critical density the ground state is a static Wigner lattice. For supercritical density the ground state has a nonzero kinetic energy. The cr...

Emergence of long-range order in sheets of magnetic dimers.

Quantum spins placed on the corners of a square lattice can dimerize and form singlets, which then can be transformed into a magnetic state as the interactions between dimers increase beyond threshold. This is a strictly 2D transition in theory, but real-world materials often need the third dimension to stabilize long-range order. We use high pressures to convert sheets of Cu(2+) spin 1/2 dimer...

Long-Range Order in the Hubbard Model

This paper begins by analyzing the Fermi-Hubbard Hamiltonian, a hopping model for Fermions on a lattice, and the pathology of the model’s extreme cases is discussed. Finally, the usefulness of experiments with ultracold atoms for studying order in these systems is presented. William R. McGehee Long-Range Order in the Hubbard Model 2

Spin liquid versus long range magnetic order in the frustrated body-centered tetragonal lattice

Two-dimensional magnetic correlations and partial long-range order in geometrically frustrated Sr2YRuO6.

Neutron diffraction on the double perovskite Sr(2)YRuO(6) with a quasi-fcc lattice of Ru moments reveals planar magnetic correlations that condense into a partial long-range ordered state with coupled alternate antiferromagnetic (AFM) YRuO(4) square layers coexisting with the short-range correlations below T(N1) = 32 K. A second transition to a fully ordered AFM state below T(N2) = 24 K is obse...