To Örebro University

The static and dynamic properties of spin polarons in La-doped CaMnO3 are explored theoretically, by means of an effective low-energy Hamiltonian. All parameters of the effective Hamiltonian are evaluated from first-principles theory. The Hamiltonian is used to investigate the temperature stability as well as the response to an external applied electric field, for spin polarons in bulk, surface, and as single two-dimensional layers. Technically this involves atomistic spin-dynamics simulations in combination with kinetic Monte Carlo simulations. Where a comparison can be made, our simulations exhibit excellent agreement with available experimental data and previous theory. Remarkably, we find that excellent control of the mobility of spin polarons in this material can be achieved, and that the critical parameters deciding this are the temperature and strength of the applied electrical field. We outline different technological implications of spin polarons, and point to spin polaronics as an emerging subfield of nanotechnology. In particular, we demonstrate that it is feasible to write and erase information on an atomic scale, by use of spin polarons in CaMnO3.