Coupling of the triple-Q state to the atomic lattice by anisotropic symmetric exchange

TL;DR

This paper demonstrates that the triple-Q magnetic state in certain bilayers is coupled to the atomic lattice through anisotropic symmetric exchange, with experimental validation and implications for topological magnetization.

Contribution

It reveals the coupling mechanism of the 3Q state to the lattice via anisotropic symmetric exchange and provides experimental confirmation of the predicted magnetic orientation.

Findings

3Q state identified as magnetic ground state in Pd/Mn and Rh/Mn bilayers

Coupling of 3Q state to lattice via anisotropic symmetric exchange confirmed

Distortions affect the orientation and topological magnetization of the 3Q state

Abstract

We identify the triple-Q (3Q) state as magnetic ground state in Pd/Mn and Rh/Mn bilayers on Re(0001) using spin-polarized scanning tunneling microscopy and density functional theory. An atomistic model reveals that in general the 3Q state with tetrahedral magnetic order and zero net spin moment is coupled to a hexagonal atomic lattice in a highly symmetric orientation via the anisotropic symmetric exchange interaction, whereas other spin-orbit coupling terms cancel due to symmetry. Our experiments are in agreement with the predicted orientation of the 3Q state. A distortion from the ideal tetrahedral angles leads to other orientations of the 3Q state which, however, results in a reduced topological orbital magnetization compared to the ideal 3Q state.