Unexpected Magnetism in Alkaline Earth Monosilicides

Abstract

Alkaline earth monosilicides (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 ∞ 1 [Si 2− ] π 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.