Recent Publications

Tchavdar Todorov

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  1. Title: Structure-related effects on the domain wall migration in atomic point contacts

    Author(s): Stamenova M., Sahoo S., Todorov T.N., Sanvito S.

    Journal Of Magnetism And Magnetic Materials, 316, No. 2, pp. E934-E936 (SEP 2007)

    doi: 10.1016/j.jmmm.2007.03.147

    We investigate the interplay between magnetic and structural dynamics in magnetic point contacts under current-carrying conditions. In particular we address the dependence of the results upon the specific parameterization of the elastic properties of the material. Our analysis shows a strong influence of the structural relaxation on the energy barrier for domain wall migration, but a negligible dependence of the mechanical properties on the magnetic state. These results are stable against the various material specific choices of parameters describing different transition metals. (c) 2007 Elsevier B.V. All rights reserved.

  2. Title: Dynamical simulation of inelastic quantum transport

    Author(s): McEniry E.J., Bowler D.R., Dundas D., Horsfield A.P., Sanchez C.G., Todorov T.N.

    Journal Of Physics-Condensed Matter, 19, No. 19, Art. No. 196201 (MAY 16 2007)

    doi: 10.1088/0953-8984/19/19/196201

    A method for correlated quantum electron-ion dynamics is combined with a method for electronic open boundaries to simulate in real time the heating, and eventual equilibration at an elevated vibrational energy, of a quantum ion under current flow in an atomic wire, together with the response of the current to the ionic heating. The method can also be used to extract inelastic current voltage corrections under steady-state conditions. However, in its present form the open-boundary method contains an approximation that limits the resolution of current-voltage features. The results of the simulations are tested against analytical results from scattering theory. Directions for the improvement of the method are summarized at the end.