A novel superhard BN allotrope under cold compression of h-BN
2013 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 25, no 12, 122204- p.Article in journal (Refereed) Published
Using first-principles calculations, we identify a new orthorhombic boron nitride (BN) phase (namely, P-BN; space group: Pmn2(1)), which has similar topological structure to Bct-BN and Z-BN, but without the six-membered ring. This P-BN allotrope is energetically more favorable than previously reported Pnma-BN, Bct-BN and Z-BN phases. With only 0.06 eV/atom less stable than h-BN at ambient pressure, it can be formed from h-BN under cold compression at a low pressure of 4 GPa. The theoretical hardness and bulk modulus of the P-BN crystal are 403 GPa and 60.5 GPa, respectively, comparable to those of c-BN. Moreover, the P-BN phase along with Bct-BN and Z-BN are suggested as possible intermediate phases between h-BN and w-BN, which can be qualitatively explained by two empirical rules of Ostwald and Ostwald-Volmer.
Place, publisher, year, edition, pages
2013. Vol. 25, no 12, 122204- p.
Boron-Nitride, Phase-Transformation, High-Temperature, High-Pressure, C-Bn, Diamond, Graphite
IdentifiersURN: urn:nbn:se:kth:diva-120282DOI: 10.1088/0953-8984/25/12/122204ISI: 000315598400004ScopusID: 2-s2.0-84874883756OAI: oai:DiVA.org:kth-120282DiVA: diva2:614860
FunderSwedish Research Council
QC 201304082013-04-082013-04-042013-07-02Bibliographically approved