Dmitry V. Fedorov

First-principle calculations of the Berry curvature of Bloch states for charge and spin transport of electrons

Recent progress in wave packet dynamics based on the insight of Berry pertaining to adiabatic evolution of quantum systems has led to the need for a new property of a Bloch state, the Berry curvature, to be calculated from first principles. We report here on the response to this challenge by the ab initio community during the past decade. First we give a tutorial introduction of the conceptual developments we mentioned above. Then we describe four methodologies which have been developed for first-principle calculations of the Berry curvature. Finally, to illustrate the significance of the new developments, we report some results of calculations of interesting physical properties such as the anomalous and spin Hall conductivity as well as the anomalous Nernst conductivity and discuss the influence of the Berry curvature on the de Haas-van Alphen oscillation.

Evaluation of conduction eigenchannels of an adatom probed by an STM tip

Ballistic conductance through a single atom adsorbed on a metallic surface and probed by a scanning tunneling microscope (STM) tip can be decomposed into eigenchannel contributions, which can be potentially obtained from shot noise measurements. Our density functional theory calculations provide evidence that transmission probabilities of these eigenchannels encode information on the modifications of the adatoms local density of states caused by its interaction with the STM tip. In the case of open shell atoms, this can be revealed in nonmonotonic behavior of the eigenchannels transmissions as a function of the tip-adatom separation.

Skew Scattering Mechanism by an Ab Initio Approach: Extrinsic Spin Hall Effect in Noble Metals

We present a first-principles study of the extrinsic spin Hall effect due to skew scattering at substitutional defects in noble metals (Cu, Ag, and Au). The dependence of the spin Hall angle on the type of impurity atoms in the host materials is discussed. We perform a detailed analysis based on the consideration of the total angular momentum dependence on scattering phase shifts of the impurity and host atoms.

PERFECT ALLOYS FOR SPIN HALL CURRENT-INDUCED MAGNETIZATION SWITCHING

We propose a device that allows for magnetization switching in nanomagnets by means of a pure spin current induced by the spin Hall effect. For this purpose we combine the ideas of magnetization sw...

Colossal spin Hall effect in ultrathin metallic films

We predict spin Hall angles up to 80% for ultrathin noble metal films with substitutional Bi impurities. The colossal spin Hall effect is caused by enhancement of the spin Hall conductivity in reduced sample dimension and a strong reduction of the charge conductivity by resonant impurity scattering. These findings can be exploited to create materials with high efficiency of charge to spin current conversion by strain engineering.

Insight into the skew-scattering mechanism of the spin Hall effect: Potential scattering versus spin-orbit scattering

We present a detailed analysis of the skew-scattering contribution to the spin Hall conductivity using an extended version of the resonant scattering model of Fert and Levy [Phys. Rev. Lett. 106, 157208 (2011)]. For 5d impurities in a Cu host, the proposed phase shift model reproduces the corresponding first-principles calculations. Crucial for that agreement is the consideration of two scattering channels related to p and d impurity states since the discussed mechanism is governed by a subtle interplay between the spin-orbit and potential scattering in both angular-momentum channels. It is shown that the potential scattering strength plays a decisive role for the magnitude of the spin Hall conductivity.

Spin Hall effect in two-dimensional systems within the relativistic phase shift model

Recently, a relativistic phase shift model (RPSM) was introduced [D. V. Fedorov et al., Phys. Rev. B 88, 085116 (2013)] to describe the skew-scattering mechanism of the spin Hall effect caused by impurities in bulk crystals. Here, we present its analog derived for two-dimensional (2D) systems. The proposed 2D-RPSM is applied to one-monolayer noble-metal films with various substitutional impurities and the obtained results are compared with those of corresponding first-principles calculations. We demonstrate that, in contrast to the three-dimensional RPSM, the considered model does not provide a sufficient qualitative description of the transport properties. Therefore, an ab initio treatment is necessary for the description of the spin Hall effect in two-dimensional crystals.