|Heisenberg model quantum spin kagome lattice Green's function method spin wave theory|
The ground state of a spin-half Heisenberg antiferromagnet on the stacked kagome lattice by using a spin-rotation-invariant Green's function method is studied. Since the pure two-dimensional kagome antiferromagnet is most likely a magnetically disordered quantum spin liquid, the question whether the coupling of kagome layers in a stacked three-dimensional system may lead to a magnetically ordered ground state is investigated. Spin-spin correlation functions and correlation lengths are presented. For comparison linear spin wave theory is also applied. The results provide strong evidence that the system remains short-range ordered independent of the sign and the strength of the interlayer coupling.