论文标题
偶联的六角形晶格中的非线性狄拉克点和拓扑不变
Nonlinear Dirac Points and topological invariant in coupled hexagonal lattices
论文作者
论文摘要
近年来，拓扑阶段和材料引起了很多关注。尽管已经取得了许多进展，但非线性对这种系统的影响仍未受到影响。在本文中，通过考虑耦合的玻色子 - 甲状腺晶格系统中的平均场近似值，我们获得了另一种类型的狄拉克锥。由于其特殊的锥体结构，该新的Dirac锥体的浆果相（二维Zak阶段）的量化不同，即，由于相互作用的类型，由于相互作用的相互作用和不同拓扑相之间的相互作用以及不同的拓扑阶段之间的临界线已经移动。此外，发现新的浆果阶段已被量化，提供了可能的非线性拓扑不变式，可以作为该相互作用系统的拓扑分类提供标准。还研究了根据系统中此标准的量子相变。
Topological phases and materials have attracted much attention in recent years. Though many progress has been made, the effect of nonlinearity on such system remains untouched. In this paper, by considering the mean-field approximation in a coupled boson-hexagonal lattice system, we obtain a different type of Dirac cone. Due to its special structure of the cone, the Berry phase (two-dimensional Zak phase) of this new Dirac cone is quantized differently, i.e., it has been modified due to the interactions and the critical line between different topological phases has moved, depending on the type of interactions. Furthermore, the new Berry phase is found to be quantized, offering a possible nonlinear topological invariant which can supply as a criterion of topological classification for that interacting system. The quantum phase transition in terms of this criterion in the system has also been examined.
