Professor Xun-li WANG, our Head of Department and Chair Professor of Physics, together with his research collaborators from Australia, Japan and United States, recently uncovered a hidden amorphous phase in the formation of metallic glass. This new breakthrough in the discovery of metallic glass formation has been published in the internationally acclaimed journal Nature Communications. 

Owing to its high resilience which can sustain larger elastic deformation, metallic glass has been used in a variety of applications including but not limited to sports equipment, medical devices and electricity transformers. Building upon the discovery of the hidden amorphous phase, where atoms show a different kind of packing, researchers hope to utilize the simple processing methods such as heat treatment to develop novel materials. The discovery solved a 40-year scientific mystery and will undoubtedly signify an important milestone in the development of new and better metallic alloys. 

Read more at: http://www.nature.com/articles/ncomms14679.

Detailed news story can also be retrieved from CityU News (20 March 2017).

The concept of geometric phase has revolutionized our understanding of state evolution in both classical and quantum physics and has led to the discovery of topological insulators. Geometric phase arising from the SO(3) group rotation of states in real space is called spin-redirection phase and can be observed in vector waves, such as light. It is commonly believed that such a phase should be absent in scalar waves, such as airborne sound. Dr. Shubo WANG and his collaborators theoretically and experimentally demonstrated, for the first time, spin-redirection phase effects in airborne sound. This is achieved by exploiting sound vortex traveling through a path that bestows a nontrivial winding of the wave vector in momentum space. It provides the important insight that the topological properties of different parameter spaces, e.g. real space and momentum space, are correlated, and one can serve as the origin of the other. The work lays the foundation for future exploitation of spin-redirection phase as a new degree of freedom for the manipulation of scalar waves. 

Read more at Science Advances: http://advances.sciencemag.org/content/4/2/eaaq1475

Related article: http://www.cityu.edu.hk/vprt/news/2018/spin-redirection-phase-of-sound-wave-demonstrated-for-the-first-time/