Unexpected Magnetism in Alkaline Earth Mono-Silicides

Abstract

Alkaline earth mono-silicides (ÆSi, Æ $=$ Ca, Sr, Ba) are poor metals and their transport properties are not solely determined by the Zintl anion, in contrast to their Zintl-type composition. Their conducting network is formed by the depopulated ${}_{\infty }^1$[Si${}^{2-}$] $\pi$-system and Æ-$d$ states. This justifies the special local coordination of the metal atoms and the planarity of the silicon chains. The low density of carriers seems to be a playground for magnetic instabilities and the triangular prismatic arrangement of Æ atoms responsible for the observed weak glassy behavior.

preprint form: 18 pages, 8 figures, 2 tables