Journal of Physics: Condensed Matter 34, 275603 (2022)

ISSN: 0953-8984, SCIE

Half-topological state in magnetic topological insulators

Minh-Tien Tran and Thanh-Mai Thi Tran

We predict a novel topological state, half-topological state, in magnetic topological insulators. The topological state is characterized by different topologies of electrons with different spin orientations, i.e., electrons with one spin orientation occupy a nontrivial topological insulating state, while electrons with opposite orientation occupy another insulating state with trivial topology. We demonstrate the occurrence of the half-topological state in magnetic topological insulators by employing a minimal model. The minimal model is a combination of the spinful Haldane and the double-exchange models. The double-exchange processes maintain a spontaneous magnetic ordering, while the next-nearest-neighbor hopping in the Haldane model gives rise to a nontrivial topological insulator. The minimal model is studied by applying the dynamical mean field theory. It is found that the long-range antiferromagnetic ordering drives the system from either topological or topologically trivial antiferromagnetic insulator to the half-topological state, and finally to topologically trivial antiferromagnetic insulator. The equations for the topological phase transitions are also explicitly derived. Keywords: magnetic topological insulator, topological phase transition, topologically breaking of spin symmetry, electron correlations (Some figures may appear in colour only in the online journal)

URL: https://doi.org/10.1088/1361-648X/ac699f

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