Associate Professor Meng Guodong and Professor Cheng Yonghong from the School of Electrical Engineering at Xi'an Jiaotong University collaborated with Associate Professor Andreas Kyritsakis from the University of Tartu in Estonia/University of Helsinki in Finland to address the issue of "Interaction between Strong Electric Fields and Electrode Materials." They proposed using high-resolution transmission electron microscopy for in-situ electrical and microstructural characterization to systematically study the morphological evolution dynamics of carbon layers on metal surfaces under extreme strong electric fields (~GV/m). For the first time internationally, the real-time generation and growth process of nano-protrusions on the surface of amorphous carbon layers were observed, and different growth stages of nano-protrusions were discovered by combining the changing characteristics of field-induced electron emission currents, revealing the intrinsic connection between material morphological evolution characteristics and field-induced electron emission properties. Recently, this research achievement was published in Physical Review Letters.
The study proposed a field-induced surface atomic diffusion mechanism, where localized high electric fields significantly alter the migration barriers between surface atoms, driving surface atoms to diffuse towards directions of higher field strength, ultimately forming precursors for breakdown and inducing breakdown. The research findings contribute to a deeper understanding of the interaction between electric fields and electrode materials during vacuum breakdown, providing insights into the initial mechanisms of vacuum breakdown at the material's microscopic scale and laying a theoretical foundation for addressing vacuum breakdown issues in high-energy physics devices and micro/nano devices.
Illustration of field-induced nanostructures formation and growth. (Provided by the research group)
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