arXiv:2003.03561 · Physical Review A
Simulation of a nodal-line semimetal in amplitude-shaken optical lattices
Tan-Ji Zhou, Zhongcheng Yu, Zhihan Li, Xuzong Chen, Xiaoji Zhou
Abstract
As the research of topological semimetals develops, semimetals with nodal-line rings have come into people's vision as a new platform for studying electronic topology. We propose a method that uses ultracold atoms in a two-dimensional amplitude-shaken bipartite hexagonal optical lattice to simulate the nodal-line semimetal, which can be achieved in the experiment by attaching one triangular optical lattice to a hexagonal optical lattice and periodically modulating the intensity and position of the triangular lattice. By adjusting the shaking frequency and well depth difference of the hexagonal optical lattice, a transformation from Dirac semimetal to the nodal-line semimetal is observed in our system. This transformation can be demonstrated by the Berry phase and Berry curvature, which guides the measurement. Furthermore, the amplitude shaking and ${C}_{3}$ symmetry generate a time-reversal-symmetry-unstable mode, and the proportion of the mode and the trivial mode of the hexagonal lattice controls the transformation. This proposal paves a way to study nodal-line semimetals in two-dimensional systems, and it contributes to the application of nodal-line semimetals.