2015 Innovation Award: Law Kam Tuen
Before the discovery of topological materials, the electronic band structure of materials was a core subject in the discipline of physics. Scientists studied the behaviour of electrons and calculated their properties. About a decade ago, scientists realised that band structure consists of two types of materials, ordinary materials and topological materials. While band structure calculation focused on bulk behaviour, this development showcased how surface properties of topological materials can be dramatically different from bulk properties. This makes topological materials useful for many applications such as making better electronics, faster computers etc.
From the time of his postdoctoral research at Massachusetts Institute of Technology as a 2008 Croucher Fellow, Law has looked into topological superconductors. A large bulk of his research is to engineer materials, namely topological superconductors, which could support Majorana fermions, detect them and manipulate them. In physics, we are always on the lookout for new particles. In research on topological superconductors in condensed matter systems, we study an exotic kind of particle called Majorana fermion. The properties of Majorana fermions are different from ordinary electrons.
“In a material or in any quantum system for example, the system is described by the wave function of the particle, and when you interchange the position of two identical particles (i.e. electrons) in this system, the property of the wave function does not change. However, in a system with Majorana fermions, the wave function would change to a completely different state. This is the property used for constructing quantum computers and it cannot be found in any other particles in the condensed matter system”, Law explains.
Other than supporting Majorana fermions, another feature of topological superconductors is that some of their properties are independent of the details of the material, such as the number of electrons and the exact lattice structure. For instance, topologically, a cup is equivalent to a donut as both their structures contain a hole. “The properties of Majorana fermions are different from ordinary electrons”.
Law is a joint recipient of the 2015 Croucher Foundation Innovation award along with Dr Shizhong Zhang from the University of Hong Kong. Zhang is researching whole atomic systems, which are essentially synthetic materials, using lasers to create optical lattices with artificial atomic sites that are filled by atoms. These atoms behave similarly to electrons in condensed matter systems, which is Law’s area of expertise. By tuning the interaction between the atoms and the optical lattice, it is possible to realise topological states in those systems. Law says that although the systems may be different, the calculations behind them are the same, giving them a chance to collaborate on certain aspects of their research.
Law is currently an Assistant Professor at the Hong Kong University of Science and Technology. He was jointly awarded the 2015 Croucher Foundation Innovation Award with HKU’s Dr Shizhong Zhang. Law has a PhD in condensed matter theory from Brown University (2008) where he received the Dissertation Fellowship and the Anthony Houghton Award for Theoretical Physics. He was awarded a Croucher Fellowship in 2008 to pursue topological states of matter at MIT.
To view Dr Law Kam Tuen’s personal Croucher profile, please click here.