Mechanism for normal chirality at hexagonal interfaces

We study the net chirality created by the Dzyaloshinkii-Moriya interaction (DMI) at the boundary between hexagonal layers of magnetic and non-magnetic materials. It is determined that another mechanism besides elastic torsion is required to understand the change in chirality observed in Dy/Y multilayers during field cooling. We show that due to the overlap between magnetic and non-magnetic atoms, interfacial steps may produce a DMI normal to the interface in magnetic heterostructures.