Understanding diamond defect formation in real time

Diamond is one of the hardest materials known to humankind. It is highly durable and can withstand extreme temperatures and pressures, so it is often used in dynamic compression experiments. But understanding how the material behaves under those conditions can be challenging.

Vennari et al. employed the Matter at Extreme Conditions beamline at the Linac Coherent Light Source to observe defect formation during high-pressure shock compression in real time.

“[Diamond] is well known to be very strong at ambient conditions and is equally the strongest material during dynamic compression,” said author Cara Vennari. “That same strength also makes its response difficult to model accurately, so experimental data are needed to improve our understanding of its material behavior.”

At low pressures, shock compression is purely elastic, but at high pressures, the compression wave splits into two parts: a fast elastic wave and a slower plastic wave. Researchers have long known about defect formation during plastic deformation, but less is known about the elastic part of the shock response.

Using single-pulse X-ray topography, the researchers observed defect creation at both ambient and extreme conditions, documenting an unexpected number of defects during the elastic wave.

“We were rather surprised at the quantity and size of the strain gradients in the topographic images during compression, which were larger than the beam size and absent in ambient images,” said Vennari. “This indicates substantial lattice distortion in the elastic wave.”

In addition to revealing more about the behavior of diamond at high pressures, the authors hope their work can serve as a template for exploring defect formation in other materials. They are already planning to expand their research in this direction, along with improving their experimental setup to produce even more high-resolution measurements.

Source: “Single-pulse X-ray topography of ambient and shock-compressed diamond,” by Cara E. Vennari, Richard Briggs, Carol Davis, Eric Folsom, Trevor Hutchinson, Kento Katagiri, Dimitri Khaghani, Bernard Kozioziemski, Dorian Luccioni, Christopher McGuire, Lauren Moghimi, Bob Nagler, Trygve M. Raeder, Raymond F. Smith, Arturas Vailionis, Xueli Zheng, Leora Dresselhaus-Marais, and Jon Eggert, Review of Scientific Instruments (2026). The article can be accessed at https://doi.org/10.1063/5.0333763 .