From 3D to 2D
A team of physicists from several institutions, including the University of Hong Kong, has made an important discovery in the field of van der Waals (vdW) magnetic materials.
They experimentally observed, for the first time, a transition in nickel phosphorus trisulfide (NiPS3), a type of vdW material with potential applications in electronic devices and energy storage, from a three-dimensional long-range order state to a two-dimensional flat pattern vestigial order state.
The researchers observed a partial symmetry change, marking a transition to a vestigial order where some symmetries persist as the primary magnetic order breaks down with thinning.
To capture the emergence of the vestigial order, the team used nitrogen-vacancy spin relaxometry and optical Raman quasi-elastic scattering. To complement their experimental findings, the researchers conducted large-scale Monte Carlo simulations using high-performance computing resources. These provided a deeper understanding of the dimensional crossover process.
This research is significant because it shows how the material changes its magnetic properties as it becomes thinner and gives insights into how to control magnetic properties of materials at very small scales, which could lead to more efficient electronics and high-density data storage.
The research team included Dr Chengkang Zhou and Professor Zi Yang Meng from the University of Hong Kong, along with Professor Rui He from Texas Tech University, and Dr Liuyan Zhao, Professor Kai Sun and Dr Zeliang Sun from the University of Michigan.
The findings were published in Nature Physics, with Zhou, Zeliang Sun, and Dr Gaihua Ye (Texas Tech University) contributing equally as first authors.