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Title: Graphene-like conjugated π bond system in Pb{sub 1−x}Sn{sub x}Se

Following the identification of the π bond in graphene, in this work, a π bond constructed through side-to-side overlap of half-filled 6p{sub z} orbitals was observed in a non-carbon crystal of Pb{sub 1–x}Sn{sub x}Se (x ∼ 0.34) (PSS), a prototype topological crystalline insulator and thermoelectric material with a high figure-of-merit. PSS compounds with a rock-salt type cubic crystal structure were found to consist of σ bond connected covalent chains of Pb(Sn)-Se with an additional π bond that is shared as a conjugated system among the four nearest neighbor Pb pairs in square symmetry within all (001) monoatomic layers per cubic unit cell. The π bond formed with half-filled 6p{sub z} orbitals between Pb atoms is consistent with the calculated results from quantum chemistry. The presence of π bonds was identified and verified with electron energy-loss spectroscopy through plasmonic excitations and electron density mapping via an inverse Fourier transform of X-ray diffraction.
Authors:
; ; ; ;  [1] ;  [2] ;  [1] ;  [3] ;  [3]
  1. Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)
  2. NISP Lab, Nano Center, University of Maryland, College Park, Maryland 20742 (United States)
  3. (China)
Publication Date:
OSTI Identifier:
22398771
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CONCENTRATION RATIO; COVALENCE; CRYSTAL STRUCTURE; CRYSTALS; ELECTRON DENSITY; ELECTRONS; ENERGY-LOSS SPECTROSCOPY; EXCITATION; FOURIER TRANSFORMATION; GRAPHENE; LAYERS; LEAD SELENIDES; PERFORMANCE; SALT DEPOSITS; THERMOELECTRIC MATERIALS; TIN COMPOUNDS; X-RAY DIFFRACTION