Current Induced Order Parameter Dynamics: Microscopic Theory Applied to Co/Cu/Co spin valves
Abstract
Transport currents can alter alter order parameter dynamics and change steady states in superconductors, in ferromagnets, and in hybrid systems. In this article we present a scheme for fully microscopic evaluation of order parameter dynamics that is intended for application to nanoscale systems. The approach relies on time-dependent mean-field-theory, on an adiabatic approximation, and on the use of non-equilibrium Greens function (NEGF) theory to calculate the influence of a bias voltage across a system on its steady-state density matrix. We apply this scheme to examine the spin-transfer torques which drive magnetization dynamics in Co/Cu/Co spin-valve structures. Our microscopic torques are peaked near Co/Cu interfaces, in agreement with most previous pictures, but suprisingly act mainly on Co transition metal -orbitals rather than on -orbitals as generally supposed.
Cite
@article{arxiv.cond-mat/0611534,
title = {Current Induced Order Parameter Dynamics: Microscopic Theory Applied to Co/Cu/Co spin valves},
author = {P. M. Haney and D. Waldron and R. A. Duine and A. S. Nunez and H. Guo and A. H. MacDonald},
journal= {arXiv preprint arXiv:cond-mat/0611534},
year = {2009}
}
Comments
9 pages, 5 figures