Two-dimensional honeycomb (A7) and zigzag sheet (ZS) type nitrogen monolayers. A first principles study of structural, electronic, spectral, and mechanical properties
2017 (Engelska)Ingår i: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 133, s. 122-129Artikel i tidskrift (Refereegranskat) Published
Abstract [en]
Two single-bonded 2D nitrogen allotropes of the honeycomb (A7) and zigzag sheet (ZS) topology have been calculated using density functional theory (DFT). The optical (vibrational, absorption, nuclear magnetic resonance), thermodynamic and elastic properties of the A7 and ZS sheets have been calculated for the first time. The band structure calculation have revealed a semiconducting nature of the ZS sheet with a direct gap of 1.246 eV, while the A7 monolayer behaves as an insulator with an indirect gap of 3.842 eV. Phonon dispersion calculations have justified these structures as vibrationally stable 2D materials. The IR spectroscopy completely failed in the characterization of the studied materials, while the Raman spectroscopy can be effectively applied for the experimental spectral identification. The absorption spectra demonstrate complete opacity of the A7 and ZS monolayers to the UV irradiation only above ca. 9 and 6 eV, respectively. Thus, the studied materials are expected to be transparent to the visible light. The electron arrangement of the nitrogen nuclei in the studied polynitrogen sheets is denser compared to the N2 molecule which follows from the calculation of the values of magnetic shielding tensors. The elastic constants reveal a robust mechanical stability of the studied 2D nitrogen allotropes. The Young moduli values are only twice as lower than that of the graphene molecule.
Ort, förlag, år, upplaga, sidor
Elsevier B.V. , 2017. Vol. 133, s. 122-129
Nyckelord [en]
2D materials, DFT, High-energy density materials, Nitrogen allotropes, Single-bonded nitrogen, Calculations, Characterization, Dispersions, Honeycomb structures, Irradiation, Magnetic shielding, Mechanical stability, Molecules, Monolayers, Nitrogen, Band structure calculation, Elastic properties, First-principles study, High energy density materials, Phonon dispersions, UV irradiation, Visible light, Young modulus, Density functional theory
Nationell ämneskategori
Materialteknik
Identifikatorer
URN: urn:nbn:se:kth:diva-207304DOI: 10.1016/j.commatsci.2017.03.007ISI: 000399611200015Scopus ID: 2-s2.0-85015456340OAI: oai:DiVA.org:kth-207304DiVA, id: diva2:1109079
Anmärkning
QC 20170613
2017-06-132017-06-132022-09-13Bibliografiskt granskad