Fully relativistic pseudopotential formalism under an atomic orbital basis: spin–orbit splittings and magnetic anisotropies

Abstract

We present an efficient implementation of the spin-orbit coupling within the density functional theory based SIESTA code (2002 J. Phys.: Condens. Matter 14 2745) using the fully relativistic and totally separable pseudopotential formalism of Hemstreet et al (1993 Phys. Rev. B 47 4238). First, we obtain the spin-orbit splittings for several systems ranging from isolated atoms to bulk metals and semiconductors as well as the Au(111) surface state. Next, and after extensive tests on the accuracy of the formalism, we also demonstrate its capability to yield reliable values for the magnetic anisotropy energy in magnetic systems. In particular, we focus on the L1(0) binary alloys and on two large molecules: Mn(6)O(2)(H -sao)(6)(O(2)CH)(2)(CH(3)OH)(4) and Co(4)(hmp)(4)(CH(3)OH)(4)Cl(4). In all cases our calculated anisotropies are in good agreement with those obtained with full-potential methods, despite the latter being, in general, computationally more demanding.

Electronic and magnetic properties of bimetallicL10cuboctahedral clusters by means of fully relativistic density-functional-based calculations

“…We have undertaken calculations of electronic structure and magnetic anisotropy energies (MAE) by means of DFT using a recent fully relativistic (FR) implementation [54] in the GREEN [56,57] code employing the SIESTA [55] framework. We use fully separable Kleinmann-Bylander [58] and norm-conserving pseudopotentials (PP) of the Troulliers-Martins [59] type to describe the core electrons.…”

“…The radius r pc should be chosen small enough to ensure that the overlap region between the valence and the core charges is fully taken into account. Based on previous studies of the binary alloys [54], we have choosen for the radius that equals the core and valence charge the values of r pc (Fe,Co) = 0.6 Bohrs and r pc (Pt,Au,Pd) = 1.0 Bohrs, ensuring that the overlap region between the valence and the core charge is fully take into account. As basis set, we have employed double-zeta polarized (DZP) strictly localized numerical atomic orbitals (AO).…”

“…Also, the magnetization density vector can vary from point to point in space presenting a spin non collinearity. To over-come this barrier we have used a fully relativistic pseudopotential (FR-PP) approach implemented recently in the SIESTA code [54,55].…”

A first principles study of thiol-capped Au nanoparticles: Structural, electronic, and magnetic properties as a function of thiol coverage

“…Finally, we address any magnetic properties after spin polarized calculations including the spin-orbit coupling (SOC) within the DFT formalism. 34 The paper is organized as follows. In Sec.…”

In-plane/out-of-plane disorder influence on the magnetic anisotropy of Fe1−yMnyPt-L1 bulk alloy

“…18 MAE is defined as the difference in the total energy between hard and easy magnetization directions, and it has been obtained using a fully relativistic (FR) implementation 19 in the GREEN 20 code employing the SIESTA framework. On the right side of the Figure 1 is shown the schematic in-plane view of three different supercell sizes with 8, 9, and 12 total number of Fe atoms, marked by A, B, and C, respectively.…”