Metastability of diamond ramp-compressed to 2TPa by Lazicki, A, McGonegle, D, Rygg, JR, Morgan, MG, Braun, DG, Swift, DC, Smith, RF, Heighway, P, Suggit, MJ, Fratanduono, DE, Higginbothom, A, Coppari, F, Wehremberg, CE, Bernier, JV, Kraus, RG, Erskine, D, Wark, JS, McNaney, JM, Collins, GW, Eggert, JH, Rudd, RE