Topological semimetal phases via periodic driving

30 May 2016. NUS scientists have discovered Floquet topological semimetal phases in a simple dynamical model.

The early years of this century witnessed remarkable competition in perusing novel topological materials that could lead to robust transport properties. In particular, a fascinating direction is to use external diving fields to manipulate topological properties of a quantum system. This direction may open up the possibility of on-demand topological states via quantum control. Recently, a team led by Prof GONG Jiangbin from the Department in Physics in NUS has advanced this topic by showing how three-dimensional (3D) topological semimetal phases can be easily obtained and simulated using 1-dimensional (1D) dynamical systems.

Detailed findings of this work, featured as Editors Suggestions by Physical Review E, indicate that periodic driving can not only tune topological states easily, but can also generate topological semimetal states that are totally absent in conventional static condensed-matter systems. The results would also motivate researchers to use low-dimensional systems to simulate even higher-dimensional topological states. As an interesting step in the near future, Prof Gong plans to study with his students the possible implications of the quantum nature of a driving field on the formation of topological states. For example, is it possible to control the topological nature of a quantum system at the single photon level?

Figure shows the quasi-energy band structure of a periodically driven system under open boundary conditions. The Fermi arcs structure characteristic of a 3D Weyl semi-metal at both quasi-energy zero and quasi-energy π can be clearly seen. [Image credit: Raditya Weda BOMANTARA].

Reference

Bomantara RW, Raghava GN, Zhou LW, Gong JB, Physical Review E 93 (2016) 022209.