Current-induced order parameter dynamics: Microscopic theory applied toCo∕Cu∕Cospin valves

2006/11/20 by P. M. Haney, Paul M. Haney, D. Waldron +7 · 2 citations
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevb.76.024404

9 pages, 5 figures

arxiv created 2006/11/20 · openalex publication_date 2007/07/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

Transport currents can alter order parameter dynamics and change steady states in superconductors, in ferromagnets, and in hybrid systems. In this paper, 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 nonequilibrium Green's function 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 surprisingly act mainly on Co transition metal d orbitals rather than on s orbitals as generally supposed.

Citations

• Exchange and correlation in atoms, molecules, and solids by the spin-density-functional formalism
• Current-driven excitation of magnetic multilayers
• ab initio modeling of open systems: charge transfer, electron conduction, and molecular switching of a C₆₀ device

Cited by

• Implementation of a nonequilibrium Green’s function method to calculate spin-transfer torque
• Spin-Orbit Coupling Induced Spin-Transfer Torque and Current Polarization in Topological-Insulator/Ferromagnet Vertical Heterostructures