A research team led by Researcher Du Chengran from the School of Physics has made a breakthrough in understanding the vibration modes and particle rearrangement in quasi-two-dimensional (quasi-2D) complex plasmas. Working in collaboration with the Max Planck Institute for Extraterrestrial Physics (Germany), the University of Düsseldorf(Germany), and the Institute of Space Materials at the German Aerospace Center, the team’s findings were recently published in Physical Review Letters—a prestigious journal of the American Physical Society (APS)—and were selected as an “Editors’ Suggestion.” The work also drew attention from Physics Magazine, an APS publication, which featured the study on its official website. The paper’s first author is Miao Yang, a master’s graduate of our university, and Researcher Du Chengran serves as the corresponding author.
In previous studies on dense colloids and simulated glasses, scientists had observed a link between plastic particle rearrangement and low-frequency vibration modes. However, whether the same relationship holds in systems governed by long-range interactions remained unclear. To explore this question, Du’s team created an amorphous plasma system using bidisperse complex plasmas containing two types of dust particles. Due to the sheath ion wake effect, interactions between the particles displayed non-reciprocal characteristics—a distinctive feature of complex plasma systems. In their experiments, the researchers used an inhomogeneous laser field to drive the rotation of an elliptical quasi-2D suspension layer, while an anisotropic confinement potential applied by a specially designed frame generated shear within the system. Their results revealed a strong correlation between local shear strain and non-phononic low-frequency transverse modes, with the correlation weakening as the shear rate increased. These findings, supported by Langevin dynamics simulations, confirm that such correlations also occur in charged particle systems with long-range and non-reciprocal interactions.
(Correlation distribution between local shear strain and low-frequency transverse mode intensity)
