Numerical study of the thermodynamics of clinoatacamite
|Title||Numerical study of the thermodynamics of clinoatacamite|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||Khatami, E., Helton J. S., and Rigol M.|
|Journal||Physical Review B|
We study the thermodynamic properties of the clinoatacamite compound, Cu2(OH)3Cl, by considering several approximate models. They include the Heisenberg model on (i) the uniform pyrochlore lattice, (ii) a very anisotropic pyrochlore lattice, and (iii) a kagome lattice weakly coupled to spins that sit on a triangular lattice. We utilize the exact diagonalization of small clusters with periodic boundary conditions and implement a numerical linked-cluster expansion approach for quantum lattice models with reduced symmetries, which allows us to solve model (iii) in the thermodynamic limit. We find a very good agreement between the experimental uniform susceptibility and the numerical results for models (ii) and (iii), which suggests a weak ferromagnetic coupling between the kagome and triangular layers in clinoatacamite. We also study thermodynamic properties in a geometrical transition between a planar pyrochlore lattice and the kagome lattice.