Effective spin-2 quasi-particles at linear dispersive five-fold degenerate points with tunable topological Chern numbers

Publication date: Available online 11 April 2019Source: Physics Letters AAuthor(s): Cheng Feng, Qiang Wang, S.N. Zhu, Hui LiuAbstractIn this work, which is based on spin-2 vectors and traceless spin-2 tensors, an effective Hamiltonian is constructed with a linearly dispersive five-fold degenerate point with spin-2 vector-momentum couplings. For the model without spin-2 vector-tensor coupling, the topological Chern numbers of five bands are calculated as 4, 2, 0, −2, −4. After including spin-2 vector-tensor coupling, separate topological Chern numbers are obtained for different couplings. A cubic lattice of atoms with five internal states is designed to realize two five-fold degenerate points. The Chern numbers of the bands can be changed by tuning the coupling coefficient. In this work we propose a theoretical design to obtain spin-2 quasi-particles.

Source: Physics Letters A - April 13, 2019 Category: Physics Source Type: research