Volume 79, Number 6, September 2007
Article Number 67004
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 23 August 2007
EPL, 79 (2007) 67004
DOI: 10.1209/0295-5075/79/67004

Quantum mechanics of spin transfer in coupled electron-spin chains

W. Kim1, L. Covaci1, 2, F. Dogan1 and F. Marsiglio1

1  Department of Physics, University of Alberta - Edmonton, Alberta, Canada, T6G 2J1
2  Department of Physics and Astronomy, University of British Columbia - Vancouver, British Columbia, Canada V6T 1Z1

received 21 April 2007; accepted in final form 31 July 2007; published September 2007
published online 23 August 2007

The manner in which spin-polarized electrons interact with a magnetized thin film is currently described by a semi-classical approach. This in turn provides our present understanding of the spin transfer, or spin torque phenomenon. However, spin is an intrinsically quantum-mechanical quantity. Here, we make the first strides towards a fully quantum-mechanical description of spin transfer through spin currents interacting with a Heisenberg-coupled spin chain. Because of quantum entanglement, this requires a formalism based on the density matrix approach. Our description illustrates how individual spins in the chain time-evolve as a result of spin transfer.

72.25.-b - Spin polarized transport.
73.23.Ad - Ballistic transport.
73.63.-b - Electronic transport in nanoscale materials and structures.

© Europhysics Letters Association 2007