Paramagnetism in the kagome compounds Zn,Mg,Cd Cu3 OH 6Cl2

Frustrated magnetism on the kagome lattice has been a fertile ground for rich and fascinating physics, ranging from experimental evidence of a spin liquid to theoretical predictions of exotic superconductivity. Among experimentally realized spin 12 kagome magnets, herbertsmithite, kapellasite, and haydeeite [ Zn,Mg Cu3 OH 6Cl2] are all well described by a three parameter Heisenberg model, but they exhibit distinctly different physics. We address the problem using a pseudofermion functional renormalization group approach and analyze the low energy physics in the experimentally accessible parameter range. Our analysis places kapellasite and haydeeite near the boundaries between magnetically ordered and disordered phases, implying that slight modifications could dramatically affect their magnetic properties. Inspired by this, we perform ab initio density functional theory calculations of Zn,Mg,Cd Cu3 OH 6Cl2 at various pressures. Our results suggest that by varying pressure and composition one can traverse a paramagnetic regime between different magnetically ordered phase