Kristall- und elektronische Struktur von LaAlSi 2 / Crystal and Electronic Structure of LaAlSi 2

LaAlSi 2 (a = 4.196(2), c = 11.437(7) Å; P3̄ml; Z = 2) was synthesized by arc-melting of preheated mixtures of the elements. The compound was investigated by means of X-ray methods and by neutron diffraction. The crystal structure can be described as a stacking variant of two different segments. The first one corresponds to the CaAl 2 Si 2 structure type (LaAl 2 Si 2 ), the second one with the A1B 2 structure type (LaSi 2 ). The segments are stacked along [001]. The electronic structure of the compound is discussed on the basis of LMTO band structure calculations.