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arXiv · 1810.00044

From frustrated magnetism to spontaneous Chern insulators

H. D. Rosales·F. A. Gómez Albarracín·P. Pujol
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Abstract

We study the behaviour of electrons interacting with a classical magnetic background via a strong Hund coupling. The magnetic background results from a Hamiltonian which favours at low temperature the emergence of a phase with non-zero scalar chirality. The strong Hund's coupling combined with the total chirality of the classical spins induces in the electrons an effective flux which results in the realisation of a band structure with non zero Chern number. First, we consider as a magnetic background a classical spin system with spontaneous net chirality. We study the Density of States (DoS) and Hall conductance in order to analyse the topological transitions, as a function of the Fermi energy and the temperature of the classical spins. We also study a similar model in which the Chern number of the filled bands can be "tuned" with the external magnetic field, resulting in a topological insulator in which the direction of the chiral edge mode can be reverted by reversing the orientantion of the magnetic field applied to the classical magnetic system.

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H. D. Rosales, F. A. Gómez Albarracín, P. Pujol. 2019-01-09. From frustrated magnetism to spontaneous Chern insulators. https://doi.org/10.1103/physrevb.99.035163

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