Derivation of the spin Hamiltonians for Fe in MgO


Autoria(s): Ferrón, Alejandro; Delgado Acosta, Fernando; Fernández-Rossier, Joaquín
Contribuinte(s)

Universidad de Alicante. Departamento de Física Aplicada

Grupo de Nanofísica

Data(s)

20/04/2016

20/04/2016

12/03/2015

Resumo

A method to calculate the effective spin Hamiltonian for a transition metal impurity in a non-magnetic insulating host is presented and applied to the paradigmatic case of Fe in MgO. In the first step we calculate the electronic structure employing standard density functional theory (DFT), based on generalized gradient approximation (GGA), using plane waves as a basis set. The corresponding basis of atomic-like maximally localized Wannier functions is derived and used to represent the DFT Hamiltonian, resulting in a tight-binding model for the atomic orbitals of the magnetic impurity. The third step is to solve, by exact numerical diagonalization, the N electron problem in the open shell of the magnetic atom, including both effects of spin–orbit and Coulomb repulsion. Finally, the low energy sector of this multi-electron Hamiltonian is mapped into effective spin models that, in addition to the spin matrices S, can also include the orbital angular momentum L when appropriate. We successfully apply the method to Fe in MgO, considering both the undistorted and Jahn–Teller (JT) distorted cases. Implications for the influence of Fe impurities on the performance of magnetic tunnel junctions based on MgO are discussed.

AF acknowledges funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration, under the PEOPLE programme, Marie Curie COFUND Actions, grant agreement number 600375 and CONICET. JFR acknowledges financial support by Generalitat Valenciana (ACOMP/2010/070), Prometeo, and MEC-Spain (FIS2013-47328-C2-2-P).

Identificador

New Journal of Physics. 2015, 17: 033020. doi:10.1088/1367-2630/17/3/033020

1367-2630

http://hdl.handle.net/10045/54313

10.1088/1367-2630/17/3/033020

Idioma(s)

eng

Publicador

IOP Publishing

Relação

http://dx.doi.org/10.1088/1367-2630/17/3/033020

info:eu-repo/grantAgreement/EC/FP7/600375

Direitos

© 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

info:eu-repo/semantics/openAccess

Palavras-Chave #Magnetism #Spin Hamiltonian #Density functional theory #Wannier #Magnetic tunnel junction #Física de la Materia Condensada
Tipo

info:eu-repo/semantics/article