Effects of filling in CoSb[subscript 3]: Local structure, band gap, and phonons from first principles

Citation Wee, Daehyun et al. " Effects of filling in CoSb[subscript 3] : Local structure, band gap, and phonons from first principles. " Physical Review B 81.4 (2010): 045204. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We use ab initio computations to investigate the effect of filler ions on the properties of CoSb 3 skutterudites. We analyze global and local structural effects of filling, using the Ba-filled system as an example. We show that the deformation of Sb network induced by the filler affects primarily nearest neighboring Sb sites around the filler site as the soft Sb rings accommodate the distortion. Rearrangement of Sb atoms affects the electronic band structure and we clarify the effect of this local strain on the band gap. We compute the phonon dispersions and identify the filler-dominated modes from the lowest-frequency optical modes at ⌫. Their weak dispersion across the Brillouin zone indicates that they are localized and a force-constant analysis shows that the filler vibration is strongly coupled with nearby Sb atoms.