Structural evolution and electronic mechanism for KBH4 phase transition from first-principles calculations
Additional Document Info
2014 Elsevier B.V. All rights reserved. The structural evolution and electronic mechanism for KBH4 phase transition have been systematically investigated using first-principles calculations. The present results demonstrate experimentally observed stability order of -KBH4 > -KBH4 > -KBH4, and the predicted transition pressure at 0 K for cubic tetragonal orthorhombic phase transformation agrees reasonably with experimental measure. The atomic process indicates that KBH4 structural evolution is closely related to rotation and deformation of [BH4]- clusters as well as shift of [BH4]- clusters and K atoms. Along with phase transformation, the band gap of KBH4 narrows, the B-H covalent bond weakens while K-H interaction enhances, the K-K anti-bonding and coulomb repulsion are also stronger.