Herbertsmithite [ZnCu3(OH)6Cl2] is often discussed as the best realization of the highly frustrated antiferromagnetic kagome lattice known so far. We employ density functional theory (DFT) calculations to determine eight exchange coupling constants of the underlying Heisenberg Hamiltonian. We find the nearest-neighbor coupling J1 to exceed all other couplings by far. However, next-nearest-neighbor kagome layer couplings of 0.019J1 and interlayer couplings of up to -0.035J 1 slightly modify the perfect antiferromagnetic kagome Hamiltonian. Interestingly, the largest interlayer coupling is ferromagnetic, even without Cu impurities in the Zn layer. In addition, we validate our DFT approach by applying it to kapellasite, a polymorph of herbertsmithite, which is known experimentally to exhibit competing exchange interactions.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Aug 5 2013|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics