Magnetic order in a spin-½ interpolating kagome/square Heisenberg antiferromagnet

The coupled cluster method is applied to a spin-half model at zero temperature (T=0), which interpolates between Heisenberg antiferromagnets (HAFs) on a kagome and a square lattice. With respect to an underlying triangular lattice the strengths of the Heisenberg bonds joining the nearest-neighbor (NN) kagome sites are J₁ ≥ 0 along two of the equivalent directions and J₂ ≥ 0 along the third. Sites connected by J₂ bonds are themselves connected to the missing NN non-kagome sites of the triangular lattice by bonds of strength J₁′ ≥ 0. When J₁′ = J₁ and J₂ =0 the model reduces to the square-lattice HAF. The magnetic ordering of the system is investigated and its T=0 phase diagram discussed. Results for the kagome HAF limit are among the best available.