Homochiral Magnetic Structures in Deposited Clusters

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The unique homochirality of biopolymers and the parity violation of the electroweak interaction are two fascinating examples where the laws of nature are different for an image and for a mirror image. We believe this is also true for the magnetic structure in metal clusters deposited on surfaces. We propose the investigation of the existence and the strength of the Dzyaloshinskii- Moriya (DM) interaction of preferably ferromagnetic clusters, e.g. Fe, Co, Ni, Ru, and Os, deposited on substrates with large nuclear numbers, e.g. W, Ir, Pt, Pb, or Bi. We argue that during the past 20 years of ab initio calculations on the magnetism of small magnetic objects deposited on substrates, magnetism has only been explained on the basis of the symmetric Heisenberg exchange and the magnetic (uniaxial) anisotropy, while the DM interaction had been either overlooked, ignored or forgotten. We will implement an approach to calculate the strength of DM interaction, the DM-vector D, based on the idea of infinitesimal rotations, in a relativistic Korringa-Kohn-Rostoker Green function (KKR-GF) method based on the density functional theory. We will prove that the strength of the DM interaction is sufficient to compete with the other interactions to produce homochiral magnetic structures. Since the DM vector D depends decisively on the symmetry of the system, clusters provide a particularly fruitful field for such studies.