文档介绍：Real-Space Tight-Binding LMTO Approach to
ic Anisotropy: Application to Nickel
Films on Copper
D. Spiˇs´ak and J. Hafner
Institut f¨ur Theoretische Physik and Center putational Materials Science,
Technische Universit¨at Wien, Wiedner Hauptstraße 8-10/136, A-1040 Vienna, Austria
Abstract. The basic ingredients of a real-space tight-binding linear-muffin-tin orbital
(RS-TB-LMTO) approach to non-collinear ism and to torque-force calculations
of the ic anisotropy are described. Applications to face-centered-tetragonal Ni
films epitaxially grown on Cu(100) substrates are presented. The tetragonal distortion
of the films is calculated using an ab-initio local-density technique, and the RS-TB-
LMTO method is used for calculating the ic anisotropy in films with up to 7
Ni monolayers. The accuracy of the approach allows for a detailed analysis of second-
and fourth-order anisotropy constants.
1 Introduction
The tight-binding linear muffin-tin orbital method [1] has proven to be a very
efficient technique for investigating the electronic and ic properties of
complex materials, both in its reciprocal- and real-space forms. Exemplary ap-
plications include disordered alloys [2,3], metallic glasses [4] and quasicrystalline
alloys [5]. Of particular interest in the study of ism are systems where
the ically ordered ground state cannot be described as a simple ferro-,
antiferro-, or ic order with all moments aligned parallel or antipar-
allel to the global axis of isation. In disordered systems petition
between ferro- and ic exchange interactions and/or fluctuating
local anisotropies can lead to the formation of a non-collinear ground-state de-
scribable as a spin-glass, a spero-, speri-, or [6]. Non-collinear
ic structures can also arise as a consequence of pensated ic
interactions in ordered pounds. The symmetry criteria for the
formation of non-collinear spin structures have been discussed in Ref. [7].
Techniques for solving the K