Quantum mechanics of spin transfer in coupled electron-spin chainsW. 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