SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 16: Poster: Transport

TT 16.17: Poster

Monday, March 27, 2023, 15:00–18:00, P2/OG4

Semi-classical vibrational dynamics in molecular junctions: Anharmonic potentials and non-linear couplings — •Martin Mäck, Samuel Rudge, and Michael Thoss — Physikalisches Institut, Universität Freiburg

Non-conservative current-induced forces can lead to vibrational instabilities in molecular junctions, even at low bias voltages [1]. A common approach is to treat the vibrational dynamics semi-classically as influenced by quantum mechanical electronic degrees of freedom. Within these treatments, the vibrational modes are often assumed to be harmonic and linearly coupled to the electronic degrees of freedom. However, at the onset of vibrational instabilities, such harmonic potentials might no longer realistically describe the dynamics.

In this contribution, we use a recently developed hierachical equations of motion (HEOM) approach [2] to semi-classical Langevin dynamics [3] to study systems for which the introduction of anharmonic potentials and non-linear electron-vibrational coupling might play an important role for the vibrational dynamics of the system.
[1] J.T. Lü, M. Brandbyge, and P. Hedegård, Nano Lett. 2010, 10, 5, 1657
[2] C. Schinabeck, A. Erpenbeck, R. Härtle, and M. Thoss, Phys. Rev. B 94, 201407
[3] S. L. Rudge, Y. Ke, and M. Thoss, arXiv: 2211.14215