In the search for an all-carbon structure that is ferromagnetic at room temperature, Ovchinnikov et al. [J. Mol. Struct. THEOCHEM 251, 133 (1991); ibid. 251, 141 (1991)] identified a possible candidate in a crystal with both sp(2) and sp(3) hybridization by means of ab initio calculations on its fragments. We have examined the structural and magnetic stability of this system in its crystalline form using hybrid density functional theory. It is found that the system is structurally unstable with respect to a previously discovered, spinless carbon polymorph. Also, the present periodic calculations show that the approach based on the examination of the magnetic properties of fragments is misleading when used to predict long-range electronic and spin interactions in this class of materials.
Pisani, L., Montanari, B., Harrison, N.M. (2009). Stability of the ferromagnetic state in a mixed sp2-sp3 carbon system. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 80(10), 1-9 [10.1103/PhysRevB.80.104415].
Stability of the ferromagnetic state in a mixed sp2-sp3 carbon system
Pisani, L.Primo
Investigation
;
2009
Abstract
In the search for an all-carbon structure that is ferromagnetic at room temperature, Ovchinnikov et al. [J. Mol. Struct. THEOCHEM 251, 133 (1991); ibid. 251, 141 (1991)] identified a possible candidate in a crystal with both sp(2) and sp(3) hybridization by means of ab initio calculations on its fragments. We have examined the structural and magnetic stability of this system in its crystalline form using hybrid density functional theory. It is found that the system is structurally unstable with respect to a previously discovered, spinless carbon polymorph. Also, the present periodic calculations show that the approach based on the examination of the magnetic properties of fragments is misleading when used to predict long-range electronic and spin interactions in this class of materials.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
