Transport through a magnetic domain wall in presence of decoherence

LUCAS J. FERNÁNDEZ; HORACIO M. PASTAWSKI

Buenos Aires

Congreso; Autumn College on Non-Equilibrium Quantum Systems; 2011

UBA - Fundación Alexander-von-Humboldt - ICAM

We address the electric resistance caused by a magnetic domain wall in nanowires. It is known that domain walls are well described by functional forms of Cabrera-Falicov. When electrons pass through the domain wall, magnetic interaction produces a rotation of the spin of the incident particle orienting it with the magnetic field at x position. This situation is treated within a discrete version of the Bogoliubov-DeGennes equations, which describe the coupling between the spin components at each position. This is a problem of dispersion in steady state. With collaboration of our group, this has been treated successfully within a Green function formalism in the local representation [GWJS04]. However, in a dynamical description, this problem could also be seen as a variant of Landau-Zener problem. The degree of adiabaticity could be controlled by the group velocity of the wave packet, the strength of the Zeeman interaction and the dispersion of the domain wall. In this problem, the presence of decoherence opens possibilities for new physics that has only recently begun to be explored with approximate methods [FJWS06]. GWJS04      V.A. Gopar, D. Weinmann, R. A. Jalabert, and R. L. Stamps, Coexistence of adiabatic and nonadiabatic spin dynamics: Electronic transport through domain walls in ferromagnetic nanowires, Phys. Rev. B 69, 014426 (2004). FJWS06       P.E. Falloon, R.A. Jalabert, D. Weinmann, and R.L. Stamps, Electron transport through disordered domain walls: Coherent and incoherent regimes, Phys. Rev. B 74, 144425 (2006)