Electronic and structural anomalies in lead chalcogenides

摘要: The rocksalt-structure PbS, PbSe, and PbTe semiconductors their alloys exhibit a series of electronic-structure anomalies relative to the II-VI system, including occurrence direct gaps at L point, anomalous order band valence-band maximum energies versus anions, negative optical bowing, band-gap pressure coefficients. We show that these result from Pb s below top valence band, setting up coupling level repulsion point. Furthermore, we find topology frustrated octahedral structure leads in random alloy two distinct bonds for each anion-cation pair predicted stabilization {ital bulk} ordered Pb{sub 2}STe CuPt-like phase. {copyright} 1997} American Physical Society}