Formation of the high pressure graphite and BC8 phases in a cold compression experiment by Raman scattering. (14th September 2013)

• Record Type: Journal Article
• Authors: Odake, Shoko; Zinin, Pavel V.; Hellebrand, Eric; Prakapenka, Vitali; Liu, Yongsheng; Hong, Shiming; Burgess, Katherine; Ming, Li‐Chung
• Is Part Of: Journal of Raman spectroscopy. Volume 44:Number 11(2013:Nov.)
• Page Start: 1596
• Page End: 1602
• Publication Date: 2013-09-14
• Subjects: Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.4372
• Languages: English
• ISSNs: 0377-0486

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>We use Raman scattering to study phase transition in the graphitic <italic>g</italic>‐BC₈ phase and graphite at high pressure up to 84 GPa. The <italic>E</italic>_{2<italic>g</italic>} Raman active mode of graphite (<italic>G</italic> peak) can be detected up to 84 GPa. We demonstrate that there is (1) a phase transition in <italic>g</italic>‐BC₈ and in graphite at 35 GPa and (2) that above 35 GPa, the <italic>g</italic>‐BC₈ and graphite transform under high pressure to possibly fully <italic>sp</italic>³‐bonded, disordered <italic>hp</italic>‐BC₈, and <italic>hp</italic>‐C phases. Below the phase transition, a polynomial fit to the <italic>G</italic> peak position <italic>versus</italic> pressure data yielded a quadratic relation; above the phase transition, it demonstrates linear behavior. The phase transition at high pressure in BC₈ system and graphite is reversible. Quenched <italic>hp</italic>‐BC₈ and <italic>hp‐C</italic> phases have the Raman spectrum typical to that of the graphitic phases. Copyright © 2013 John Wiley &amp; Sons, Ltd.</p> </abstract>