Relativistic calculation of magnetic linear response functions using the Korringa–Kohn–Rostoker Green's function method

Abstract

The relativistic KKR (Korringa–Kohn–Rostoker) Green's function method of band-structure calculation supplies an extremely flexible basis for calculating magnetic linear response functions of solids. An important feature of this approach is that it accounts properly for the influence of all relativistic effects. A brief introduction to this formalism is presented, together with some recent extensions to it. In particular, the inclusion of the orbital magnetization density induced by an external magnetic field allows a direct comparison with experiment for many different properties. This is demonstrated for the induced magnetic form factor, the magnetic susceptibility and the Knight shift of transition metals. A further appealing feature of the KKR formalism is that it is applicable in principle to any complex system. This property is exemplified by applications for the disordered alloy systems AgxPd1−x and AgxPt1−x that are treated with the help of the coherent potential approximation alloy theory.

Finite-temperature magnetism ofFexPd1−xandCoPolesya1, Mankovsky2, Šipr3 et al. 2010Phys. Rev. B452370View full textAdd to dashboardCite

“…This is especially true for ordered CoPt 3 , where an antiferromagnetic order is established at finite temperatures (reflected by a negative value for T C ) if the coupling between moments on Co and Pt is ignored. The magnetic moment induced on site i (Pd or Pt) by the exchange field B xc j due to magnetic moments at site j can be calculated within the linear response formalism using the expression [52]:…”

Magnetic-field-induced effects in the electronic structure of itinerant d- and f-metal systems

“…The χ so term is a relativistic correction to the susceptibility, and it has been shown [6,7], that χ so is a higher order term as compared with χ spin and χ orb , and its value was estimated to be much smaller than the other two terms for transition metals (about few percents). Hence χ so has been usually neglected in theoretical studies of magnetic susceptibility of transition metals [5,[9][10][11][12][13].…”

“…5-7 to calculate the corresponding wave-vector dependent susceptibilities χ( ) q by using a realistic band structure of some transition metals, and then taking the limit q → 0 either analytically [5] or by numerical extrapolation [6,7]. Also the linear response formalism based on a Green's function technique was employed to calculate the spin [10,11,13] and orbital [13] magnetic susceptibilities in some transition metals. In these calculations the exchange enhancement of the Pauli spin susceptibility was taken into account within the Stoner model.…”

Nickel: The time-reversal symmetry conserving partner of iron on a chalcogenide topological insulator

“…This result suggests the use of the Stoner criterion (I χ 0 ) k can be split into the Stoner integral I k and the enhanced spin susceptibility χ k 0 = 2μ B n k (E F ), where n k (E F ) is the DOS at E F . For the more general case of an alloy and adatoms considered here, we express (I χ 0 ) k using linear response theory, as suggested by Deng et al [33] (see SM [25] For Fe atoms, our self-consistent calculations give a Stoner product (I χ 0 ) Fe = 2.68 well above 1, while for Ni we find only (I χ 0 ) Ni = 0.78. We thus can understand the quenching mechanism on the atomic level surprisingly well within the Stoner model, triggered by a critically low DOS at E F on the Ni site close to the edge of the Ni d band (Fig.…”