2023/12/01 by Lee, Kok Wai, Fu, Pei-Hao, Ang, Yee Sin · 2 citations
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Strongly Correlated Electrons (cond-mat.str-el)
paper · doi:10.48550/arxiv.2312.00642
We study the topological properties of the Haldane and modified Haldane models in α-T3 lattice. The band structures and phase diagrams of the system are investigated. Individually, each model undergoes a distinct phase transition: (i) the Haldane-only model experiences a topological phase transition from the Chern insulator (C = 1) phase to the higher Chern insulator (C = 2) phase; while (ii) the modified-Haldane-only model experiences a phase transition from the topological metal (C = 2) phase to the higher Chern insulator (C = 2) phase and we show that C is insufficient to characterize this system because C remains unchanged before and after the phase transition. By plotting the Chern number and C phase diagram, we show that in the presence of both Haldane and modified Haldane models in the α-T3 lattice, the interplay between the two models manifests three distinct topological phases, namely the C = 1 Chern insulator (CI) phase, C = 2 higher Chern insulator (HCI) phase and C = 2 topological metal (TM) phase. These results are further supported by the α-T3 zigzag edge states calculations. Our work elucidates the rich phase evolution of Haldane and modified Haldane models as α varies continuously from 0 to 1 in an α-T3 model.