Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Role of Dzyaloshinskii-Moriya interaction for magnetism in
  transition-metal chains at Pt step-edges   We explore the emergence of chiral magnetism in one-dimensional monatomic Mn,
Fe, and Co chains deposited at the Pt(664) step-edge carrying out an ab-initio
study based on density functional theory (DFT). The results are analyzed
employing several models: (i) a micromagnetic model, which takes into account
the Dzyaloshinskii-Moriya interaction (DMI) besides the spin stiffness and the
magnetic anisotropy energy, and (ii) the Fert-Levy model of the DMI for diluted
magnetic impurities in metals. Due to the step-edge geometry, the direction of
the Dzyaloshinskii vector (D-vector) is not predetermined by symmetry and
points in an off-symmetry direction. For the Mn chain we predict a long-period
cycloidal spin-spiral ground state of unique rotational sense on top of an
otherwise atomic-scale antiferromagnetic phase. The spins rotate in a plane
that is tilted relative to the Pt surface by $62^\circ$ towards the upper step
of the surface. The Fe and Co chains show a ferromagnetic ground state since
the DMI is too weak to overcome their respective magnetic anisotropy barriers.
Beyond the discussion of the monatomic chains we provide general expressions
relating ab-initio results to realistic model parameters that occur in a
spin-lattice or in a micromagnetic model. We prove that a planar homogeneous
spiral of classical spins with a given wave vector rotating in a plane whose
normal is parallel to the D-vector is an exact stationary state solution of a
spin-lattice model for a periodic solid that includes Heisenberg exchange and
DMI. The validity of the Fert-Levy model for the evaluation of micromagnetic
DMI parameters and for the analysis of ab-initio calculations is explored for
chains. The results suggest that some care has to be taken when applying the
model to infinite periodic one-dimensional systems.

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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th