Vortices, skyrmions, and chirality waves in frustrated Mott insulators with a quenched periodic array of impurities

TL;DR

This paper explores how a periodic array of nonmagnetic impurities in frustrated Mott insulators induces diverse chiral magnetic phases, including vortex and skyrmion crystals, influenced by impurity arrangement and disorder.

Contribution

It demonstrates that impurity superlattices can stabilize complex magnetic orders in frustrated magnets, revealing a rich phase diagram with novel chiral phases and effects of impurity disorder.

Findings

Periodic impurities induce vortex and skyrmion magnetic phases.

Impurity arrangement strongly influences the magnetic phase diagram.

Small disorder in impurity placement affects the stability of magnetic phases.

Abstract

Finite-${\mathbf Q}$ magnetic instabilities are rather common in frustrated magnets. When the magnetic susceptibility is maximized at multiple-${\mathbf Q}$ vectors related through lattice symmetry operations, exotic magnetic orderings such as vortex and skyrmion crystals may follow. Here we show that a periodic array of nonmagnetic impurities, which can be realized through charge density wave ordering, leads to a rich phase diagram featuring a plethora of chiral magnetic phases, especially when there is a simple relation between the reciprocal vectors of the impurity superlattice and the magnetic ${\mathbf Q}$-vectors. We also investigate the effect of changing the impurity concentration or disturbing the impurity array with small quenched randomness. Alternative realizations of impurity superlattices are briefly discussed.