Attila Szilva

Higher-order contributions to the Rashba-Bychkov effect with application to the Bi/Ag(111) surface alloy

In order to explain the anisotropic Rashba-Bychkov effect observed in several metallic-surface-state systems, we use k⋅p perturbation theory with a simple group-theoretical analysis and construct effective Rashba Hamiltonians for different point groups up to third order in the wave number. We perform relativistic ab initio calculations for the (3√×3√)R30∘ Bi/Ag(111) surface alloy, and from the calculated splitting of the band dispersion we find evidence of the predicted third-order terms. Furthermore, we derive expressions for the corresponding third-order Rashba parameters to provide a simple explanation of the qualitative difference concerning the Rashba-Bychkov splitting of the surface states at Au(111) and Bi/Ag(111).

Exchange interaction between magnetic adatoms on surfaces of noble metals

We present first-principles calculations of the exchange interactions between magnetic impurities deposited on (001), (110), and (111) surfaces of Cu and Au and analyze them, in particular, in the asymptotic regime. For the (110) and the (111) surfaces, we demonstrate that the interaction shows an oscillatory behavior as a function of the distance, R, of the impurities and that the amplitude of the oscillations decays as 1/R2. Furthermore, the frequency of the oscillations is closely related to the length of the Fermi vector of the surface states existing on these surfaces. Due to the asymmetry of the surface-states dispersion, the frequency of the oscillations becomes also asymmetric on the (110) surfaces, while on the Au(111) surface two distinct frequencies are found in the oscillations as a consequence of the Bychkov-Rashba splitting of the surface states. Remarkably, no long-range oscillations of the exchange interaction are observed for the (001) surfaces where the surface states are unoccupied. When burying the impurities beneath the surface layer, oscillations mediated by the bulk states become visible.

Magnetism and ultrafast magnetization dynamics of Co and CoMn alloys at finite temperature

Temperature-dependent magnetic experiments such as pump-probe measurements generated by a pulsed laser have become a crucial technique for switching the magnetization in the picosecond time scale. ...

Friedel-oscillations-induced surface magnetic anisotropy

We present detailed numerical studies of the magnetic anisotropy energy of a magnetic impurity near the surface of metallic hosts (Au and Cu) that we describe in terms of the tight-binding surface Greens-function technique. We study the case when spin-orbit coupling originates from the

Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe

d

Universal distribution of magnetic anisotropy of impurities in ordered and disordered nanograins

band of the host material and we also investigate the case of a strong local spin-orbit coupling on the impurity itself. The splitting of the impuritys spin states is calculated to leading order in the exchange interaction between the impurity and the host atoms using the diagrammatic Greens-function technique. The magnetic anisotropy constant is an oscillating function of the separation

Anisotropy of exchange interactions between impurities on Cu(110) surface

d

Surface-Induced Magnetic Anisotropy of Impurities

from the surface. It asymptotically decays as

Magnetic and electronic structure of Mn nanostructures on Ag(111) and Au(111)

\ensuremath{\sim}1/{d}^{2}

First-principles Dzyaloshinskii-Moryia interaction in a non-collinear framework

and its oscillation period is determined by the extremal vectors of the hosts Fermi surface. Our results clearly show that the host-induced magnetic anisotropy energy is by several orders of magnitude smaller than the anisotropy induced by the local mechanism, which provides sufficiently large anisotropy values to explain the size dependence of the Kondo resistance observed experimentally.