Electrodynamics of MnBi2Te4 intrinsic magnetic topological insulators

Electric-magnetic duality and topological insulators.

We work out the action of the SL(2,Z) electric-magnetic duality group for an insulator with a nontrivial permittivity, permeability, and theta angle. This theory has recently been proposed to be the correct low-energy effective action for topological insulators. As applications, we give manifestly SL(2,Z) covariant expressions for the Faraday rotation at orthogonal incidence at the interface of...

Electrically Tunable Magnetism in Magnetic Topological Insulators.

The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hen...

Intrinsic Two-Dimensional Organic Topological Insulators in Metal-Dicyanoanthracene Lattices.

We predict theoretical existence of intrinsic two-dimensional organic topological insulator (OTI) states in Cu-dicyanoanthracene (DCA) lattice, a system that has also been grown experimentally on Cu substrate, based on first-principle density functional theory calculations. The pz-orbital Kagome bands having a Dirac point lying exactly at the Fermi level are found in the freestanding Cu-DCA lat...

Topological insulators

Enhancement of surface photocurrents in topological insulators using magnetic superlattices

The gapless surface states of topological insulators (TI) can potentially be used to detect and harvest low-frequency infrared light. Nonetheless, it was shown that significant surface photocurrents due to light with frequency below the bulk gap are rather hard to produce. Here we demonstrate that a periodic magnetic pattern added to the surface dramatically enhances surface photocurrents in TI...