Speaker
Prof.
Hubert Ebert
Description
A theoretical description of the anomalous Hall effect (AHE) [1] and spin Hall effect (SHE) [2] based on the Kubo linear response formalism is presented giving the corresponding conductivity tensors via an appropriate form of the Kubo-Streda and Kubo-Bastin equations. The underlying electronic structure is treated using the fully relativistic multiple scattering or Korringa-Kohn-Rostoker (KKR) band structure method set up in the framework of local spin-density functional theory (LSDA). To deal with the SHE a corresponding relativistic form for the spin current density operator is used [3]. Application to disordered alloys is achieved by making use of the Coherent Potential Approximation alloy theory that in particular allows to account for the vertex corrections. Using the connection of these and the extrinsic contributions to the Hall conductivities a decomposition into intrinsic and extrinsic contributions is performed for various alloy systems. In addition the extrinsic contributions are split into skew scattering and side jump contributions via their scaling behavior. For diluted transition metal alloys, this approach leads to results in very good agreement with those obtained on the basis of the Boltzmann formalism. Using standard relations between response functions with respect to an electrical field and a temperature gradient, the scheme to calculate the AHE and SHE has been extended to deal with the corresponding anomalous Nernst effect (ANE) and spin Nernst effect (SNE) [4]. First results will be presented.
References
[1] S. Lowitzer, D. Ködderitzsch, and H. Ebert, Phys. Rev. Letters 105, 266604 (2011)
[2] S. Lowitzer, M. Gradhand, D. Ködderitzsch, D. V. Fedorov, I. Mertig, and H. Ebert, Phys. Rev. Letters 106, 056601 (2011)
[3] S. Lowitzer, D. Ködderitzsch, and H. Ebert, Phys. Rev. B 82, 140402(R) (2010)
[4] S. Wimmer, D. Ködderitzsch, K. Chadova and H. Ebert, arXiv:1306.0621v1, (2013)
