<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Luiz G. Pimenta Martins</style></author><author><style face="normal" font="default" size="100%">Diego L. Silva</style></author><author><style face="normal" font="default" size="100%">Jesse S. Smith</style></author><author><style face="normal" font="default" size="100%">Ang-Yu Lu</style></author><author><style face="normal" font="default" size="100%">Cong Su</style></author><author><style face="normal" font="default" size="100%">Marek Hempel</style></author><author><style face="normal" font="default" size="100%">Connor Occhialini</style></author><author><style face="normal" font="default" size="100%">Xiang Ji</style></author><author><style face="normal" font="default" size="100%">Ricardo Pablo</style></author><author><style face="normal" font="default" size="100%">Rafael S. Alencar</style></author><author><style face="normal" font="default" size="100%">Alan C.R. Souza</style></author><author><style face="normal" font="default" size="100%">Alysson A. Pinto</style></author><author><style face="normal" font="default" size="100%">de Oliveira, Alan B.</style></author><author><style face="normal" font="default" size="100%">Batista, Ronaldo J. C.</style></author><author><style face="normal" font="default" size="100%">Tomás Palacios</style></author><author><style face="normal" font="default" size="100%">Mazzoni, Mário S. C.</style></author><author><style face="normal" font="default" size="100%">Matos, Matheus J. S.</style></author><author><style face="normal" font="default" size="100%">Riccardo Comin</style></author><author><style face="normal" font="default" size="100%">Kong, Jing</style></author><author><style face="normal" font="default" size="100%">Luiz G. Cançado</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Hard, transparent, sp3-containing 2D phase formed from few-layer graphene under compression</style></title><secondary-title><style face="normal" font="default" size="100%">Carbon</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2020</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0008622320311179</style></url></web-urls></urls><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Despite several theoretically proposed two-dimensional (2D) diamond structures, experimental efforts to obtain such structures are in initial stage. Recent high-pressure experiments provided significant advancements in the field, however, expected properties of a 2D-like diamond such as sp3 content, transparency and hardness, have not been observed together in a compressed graphene system. Here, we compress few-layer graphene samples on SiO2/Si substrate in water and provide experimental evidence for the formation of a quenchable hard, transparent, sp3-containing 2D phase. Our Raman spectroscopy data indicates phase transition and a surprisingly similar critical pressure for two-, five-layer graphene and graphite in the 4-6 GPa range, as evidenced by changes in several Raman features, combined with a lack of evidence of significant pressure gradients or local non-hydrostatic stress components of the pressure medium up to ≈ 8 GPa. The new phase is transparent and hard, as evidenced from indentation marks on the SiO2 substrate, a material considerably harder than graphene systems. Furthermore, we report the lowest critical pressure (≈ 4 GPa) in graphite, which we attribute to the role of water in facilitating the phase transition. Theoretical calculations and experimental data indicate a novel, surface-to-bulk phase transition mechanism that gives hint of diamondene formation.</style></abstract></record></records></xml>