Artículos de revistas
Ground-state functional for quantum spin chains with bond defects
Fecha
2010Registro en:
PHYSICAL REVIEW B, v.82, n.9, 2010
1098-0121
10.1103/PhysRevB.82.092401
Autor
PENTEADO, Poliana H.
LIBERO, Valter Luiz
Institución
Resumen
We have developed a nonlocal functional of the exchange interaction for the ground-state energy of quantum spin chains described by the Heisenberg Hamiltonian. An alternating chain is used to obtain the correlation energy and a local unit-cell approximation is defined in the context of the density-functional theory. The agreement with our exact numerical data, for small chains, is significantly better than a previous formulation, even for chains with several ferromagnetic or antiferromagnetic bond defects. The results can be particularly relevant in the study of finite spin-1/2 Heisenberg chains, with exchange couplings changing, magnitude, or even sign, from bond-to-bond.