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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 84: Molecular Electronics and Photonics (joint session TT/CPP)
CPP 84.3: Vortrag
Mittwoch, 18. März 2020, 18:30–18:45, HSZ 304
Ab initio study of current-induced forces in nanojunctions — •Susanne Leitherer1, Nick Papior2, Jing-Tao Lü3, and Mads Brandbyge1 — 1Department of Physics, Technical University of Denmark — 2Department of Applied Mathematics and Computer Science, Technical University of Denmark — 3School of Physics, Huazhong University of Science and Technology, Wuhan, China
In ballistic nanoscale conductors the high current density can lead to substantial changes in the atomic structure, as seen in experiments [1]. We calculate the current-induced forces on the atoms of different models of nanojunctions under a high applied bias voltage, employing first principles electronic structure and transport calculations. Our findings show how the forces on the atoms are related to the chemical bonds, as evidenced in scanning probe experiments exploring currents and forces between two C60 molecules [2], as well as the electrostatic potential landscape in the junctions [3]. To study further the dynamical motion of atoms in nanojunctions including current-induced forces, we perform molecular dynamics simulations based on a semi-classical Langevin approach in combination with DFT calculations [4]. This allows us to study the influence of Joule heating, i.e. inelastic scattering by phonons, as well as other contributions to current-induced forces that do not conserve the energy of the atomic motion.
[1] C. Schirm et al., Nat. Nanotechnol. 8, 645-648 (2013)
[2] J. Brand et al., Nano Lett. 19, 7845-7851 (2019)
[3] S. Leitherer et al.,Phys. Rev. B 100, 035415 (2019)
[4] J.T. Lü et al., Manuscript in preparation