Journal Article

Non-thermal structural transformation of diamond driven by x-rays

Höppner, Hauke, Toleikis, Sven, Kapcia, Konrad J., Falcone, Roger, Heimann, Philip, Hartley, Nicholas J., Antoine, Andre, Inubushi, Yuichi, Martinez, Paloma, Medvedev, Nikita, Lee, Hae Ja, Yabashi, Makina, Yamada, Jumpei, Tkachenko, Victor, Ziaja, Beata, Yabuuchi, Toshinori, Gaudin, Jérôme, Tavella, Franz, Inoue, Ichiro, Dorchies, Fabien, Lipp, Vladimir

2023

Overview

Intense x-ray pulses can cause the non-thermal structural transformation of diamond. At the SACLA XFEL facility, pump x-ray pulses triggered this phase transition, and probe x-ray pulses produced diffraction patterns. Time delays were observed from 0 to 250 fs, and the x-ray dose varied from 0.9 to 8.0 eV/atom. The intensity of the (111), (220), and (311) diffraction peaks decreased with time, indicating a disordering of the crystal lattice. From a Debye–Waller analysis, the rms atomic displacements perpendicular to the (111) planes were observed to be significantly larger than those perpendicular to the (220) or (311) planes. At a long time delay of 33 ms, graphite (002) diffraction indicates that graphitization did occur above a threshold dose of 1.2 eV/atom. These experimental results are in qualitative agreement with XTANT+ simulations using a hybrid model based on density-functional tight-binding molecular dynamics.

• Publisher: American Crystallographic Association/AIP
• Subject: Carbon based materials / Chemistry / Density-functional tight-binding / Free electron lasers / INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY / Molecular dynamics / Phase transitions / Physics