Journal Article

PUBDB-2021-00588

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Phonon Spectroscopy in Antimony and Tellurium Oxides

Jafari, A. (Corresponding author)Extern*DESY* ; Klobes, B. ; Sergeev, I.DESY* ; Moseley, D. H. ; Manley, M. E. ; Dronskowski, R.Extern* ; Deringer, V. L. ; Stoffel, R. P.Extern* ; Bessas, D. ; Chumakov, A. I.Extern* ; Rüffer, R.Extern* ; Mahmoud, A.Extern* ; Bridges, C. A. ; Daemen, L. L. ; Cheng, Y. ; Ramirez-Cuesta, A. J. ; Hermann, R. P. (Corresponding author)Extern*

2020
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acs.jpca.0c05060

Abstract: α-Sb2O3 (senarmontite), β-Sb$_2$O$_3$ (valentinite), and α-TeO$_2$ (paratellurite) are compounds with pronounced stereochemically active Sb and Te lone pairs. The vibrational and lattice properties of each have been previously studied but often lead to incomplete or unreliable results due to modes being inactive in infrared or Raman spectroscopy. Here, we present a study of the relationship between bonding and lattice dynamics of these compounds. Mössbauer spectroscopy is used to study the structure of Sb in α-Sb$_2$O$_3$ and β-Sb$_2$O$_3$, whereas the vibrational modes of Sb and Te for each oxide are investigated using nuclear inelastic scattering, and further information on O vibrational modes is obtained using inelastic neutron scattering. Additionally, vibrational frequencies obtained by density functional theory (DFT) calculations are compared with experimental results in order to assess the validity of the utilized functional. Good agreement was found between DFT-calculated and experimental density of phonon states with a 7% scaling factor. The Sb–O–Sb wagging mode of α-Sb$_2$O$_3$ whose frequency was not clear in most previous studies is experimentally observed for the first time at ∼340 cm$^{–1}$. Softer lattice vibrational modes occur in orthorhombic β-Sb$_2$O$_3$ compared to cubic α-Sb$_2$O$_3$, indicating that the antimony bonds are weakened upon transforming from the molecular α phase to the layer-chained β structure. The resulting vibrational entropy increase of 0.45 ± 0.1 k$_B$/Sb$_2$O$_3$ at 880 K accounts for about half of the α–β transition entropy. The comparison of experimental and theoretical approaches presented here provides a detailed picture of the lattice dynamics in these oxides beyond the zone center and shows that the accuracy of DFT is sufficient for future calculations of similar material structures.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Experimentebetreuung PETRA III (FS-PET-S)

Research Program(s):

1. 6212 - Quantum Condensed Matter: Magnetism, Superconductivity (POF3-621) (POF3-621)
2. 6G3 - PETRA III (POF3-622) (POF3-622)

Experiment(s):

1. PETRA Beamline P01 (PETRA III)

Appears in the scientific report 2020

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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