"Synthesis of quenchable amorphous diamond"

Zhidan Zeng: Liuxiang Yang, Qiaoshi Zeng, Hongbo Lou , Hongwei Sheng , Jianguo Wen, Dean J. Miller, Yue Meng, Wenge Yang, Wendy L. Mao & Ho-kwang Mao; Nat Commun., 08/22/17.

Additional Authors: Liuxiang Yang, Qiaoshi Zeng, Hongbo Lou , Hongwei Sheng , Jianguo Wen, Dean J. Miller, Yue Meng, Wenge Yang, Wendy L. Mao & Ho-kwang Mao

Abstract:

Diamond owes its unique mechanical, thermal, optical, electrical, chemical, and biocompatible materials properties to its complete sp3-carbon network bonding. Crystallinity is another major controlling factor for materials properties. Although other Group-14 elements silicon and germanium have complementary crystalline and amorphous forms consisting of purely sp3 bonds, purely sp3-bonded tetrahedral amorphous carbon has not yet been obtained. In this letter, we combine high pressure and in situ laser heating techniques to convert glassy carbon into “quenchable amorphous diamond”, and recover it to ambient conditions. Our X-ray diffraction, high-resolution transmission electron microscopy and electron energy-loss spectroscopy experiments on the recovered sample and computer simulations confirm its tetrahedral amorphous structure and complete sp3 bonding. This transparent quenchable amorphous diamond has, to our knowledge, the highest density among amorphous carbon materials, and shows incompressibility comparable to crystalline diamond.