Finding the order in complexity: The electronic structure of 14-1-11 zintl compounds

Yb14MnSb11 and Yb14MgSb11 have rapidly risen to prominence as high-performing p-type thermoelectric materials. However, the fairly complex crystal structure of A14MX11 Zintl compounds renders interpretation electronic band obscure, making it difficult chemically guide engineering optimization efforts. In this work, we delineate valence-balanced chemistry using molecular orbital theory. By analyzing structures Yb14AlSb11, show that conduction minimum is composed either an antibonding originating from (Sb3)7– trimer or a mix atomic orbitals A, M, X. The singly degenerate valence comprised non-bonding Sb pz primarily atoms in (MSb4)m– tetrahedra isolated distributed throughout unit cell. Such chemical understanding enables strategies engineer properties (e.g., bandgap) compounds.