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

Journal Article · Mon Mar 23 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4915611· OSTI ID:22398771

Shu, G. J.; Karna, S.; Sankar, R.; Hayashi, M.; Chu, M. -W. ^[1]; Liou, S. C. ^[2]

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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)

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.

• OSTI ID: 22398771
• Journal Information: Applied Physics Letters, Vol. 106, Issue 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

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