Magnetic order in a spin-1/2 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.