Imprinting bulk metallic glass with sub-atomic precision

Nanoimprinting has drawn much interest as it can be used in a wide range of applications such as high-density storage, photonic devices, bio-nanofluidic chips, holograms and electrodes in fuel cells. In order to assess nanoimprinting’s suitability for a given application, one needs to know the size of the smallest reproducible features and the smoothness of exposed surfaces when creating molds and replicas. Zhou et al. explored the fundamental limits of nanoimprinting to accurately reproduce a given mold’s surface.

The researchers nanoimprinted bulk metallic glass using differently oriented single-crystalline LaAlO₃ surfaces with atomic-scale replication fidelity through thermoplastic forming, taking advantage of the nature of glass and the omnidirectional quality of the bonds of their metallic constituents. When heated above the glass transition temperature, the scientists could weaken the material’s internal cohesion by just the appropriate amount to manipulate it as needed.

“We now have a method that can replicate surfaces with sub-atomic precision cost-effectively,” said author Udo Schwarz. “And it all hinges on the fact that I can move the atoms in metallic glasses to virtually any place I want with picometer accuracy.”

In addition to broadening the range of applications possible using thermoplastic forming and atomic imprinting in precision nanofabrication, the research also offers a material system that allows for the continuous tuning of structural surface features for fundamental high-resolution and local studies of glass properties and behavior.

“The next step one could pursue is to replicate biomimetic surfaces, such as for low friction, low or high adhesion, and superhydrophobic or superhydrophilic surfaces and to get these properties into surfaces covering actual workpieces,” said Schwarz.

Source: “Atomic imprinting in the absence of an intrinsic length scale,” by Chao Zhou, Amit Datye, Zheng Chen, Georg H. Simon, Xinzhe Wang, Jan Schroers, and Udo D. Schwarz, APL Materials (2020). The article can be accessed at https://doi.org/10.1063/5.0027982 .