Electronic and Bonding Properties of BaGaGeH: Hydrogen-induced Metal-insulator Transition from the AlB2-type BaGaGe Precursor

Bulletin of the Korean chemical society

Dae-Bok Kang¹ 

关键词: Metal hydride;    Zintl phase;    Electronic structure;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

The hydrogenation of AlB2-type BaGaGe exhibits a metal to insulator (MI) transition, inducing a puckering distortion of the original hexagonal [GaGe] layers. We investigate the electronic structure changes associated with the hydrogen-induced MI transition, using extended Hückel tight-binding band calculations. The results indicate that hydrogen incorporation in the precursor BaGaGe is characterized by an antibonding interaction of π on GaGe with hydrogen 1s and the second-order mixing of the singly occupied antibonding π * orbital into it, through Ga-H bond formation. As a result, the fully occupied bonding π band in BaGaGe changes to a weakly dispersive band with Ge pz (lone pair) character in the hydride, which becomes located just below the Fermi level. The Ga-Ge bonds within a layered polyanion are slightly weakened by hydrogen incorporation. A rationale for this is given.

【 授权许可】

Unknown