title: Crystal structure of graphite under room-temperature compression and decompression.
abstract: Recently, sophisticated theoretical computational studies have proposed several new crystal structures of carbon (e.g., bct-C(4), H-, M-, R-, S-, W-, and Z-carbon). However, until now, there lacked experimental evidence to verify the predicted high-pressure structures for cold-compressed elemental carbon at least up to 50 GPa. Here we present direct experimental evidence that this enigmatic high-pressure structure is currently only consistent with M-carbon, one of the proposed carbon structures. Furthermore, we show that this phase transition is extremely sluggish, which led to the observed broad x-ray diffraction peaks in previous studies and hindered the proper identification of the post-graphite phase in cold-compressed carbon.
authors: Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA. ywang235@oakland.edu
authors: Yuejian
authors: Y
authors: Wang
authors: Joseph E
authors: JE
authors: Panzik
authors: Boris
authors: B
authors: Kiefer
authors: Kanani K M
authors: KK
authors: Lee