Simulating bistable current-induced switching of metallic atomic contacts by electron-vibration scattering
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| Main Authors: | , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866914779563556864 |
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| author | Ring, Markus Pauly, Fabian Nielaba, Peter Scheer, Elke |
| author_facet | Ring, Markus Pauly, Fabian Nielaba, Peter Scheer, Elke |
| contents | We present a microscopic model, describing current-driven switching in metallic atomic-size contacts. Applying a high current through an atomic-size contact, creates a strong electronic nonequilibrium that excites vibrational modes by virtue of the electron-vibration coupling. Using density functional theory (DFT) in combination with the Landauer-Büttiker theory for phase-coherent transport, expressed in terms of nonequilibrium Green's functions (NEGFs), we study the current-induced forces arising from this nonequilibrium and determine those vibrational modes which couple most strongly to the electronic system. For single-atom lead (Pb) contacts we show specific candidates for bistable switches, consisting of two similar atomic configurations with differing electric conductance. We identify vibrational modes that induce a transition between these configurations. Our results reveal a possible origin of bistable switching in atomic-size contacts through excitation of vibrations by inelastic electron scattering and underline the power of the combined DFT-NEGF approach and statistical mechanics analysis of a Langevin equation to overcome the time-scale gap between atomic motion and rare switching events, allowing for an efficient exploration of the contacts' configurational phase space. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2303_03309 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Simulating bistable current-induced switching of metallic atomic contacts by electron-vibration scattering Ring, Markus Pauly, Fabian Nielaba, Peter Scheer, Elke Mesoscale and Nanoscale Physics Materials Science We present a microscopic model, describing current-driven switching in metallic atomic-size contacts. Applying a high current through an atomic-size contact, creates a strong electronic nonequilibrium that excites vibrational modes by virtue of the electron-vibration coupling. Using density functional theory (DFT) in combination with the Landauer-Büttiker theory for phase-coherent transport, expressed in terms of nonequilibrium Green's functions (NEGFs), we study the current-induced forces arising from this nonequilibrium and determine those vibrational modes which couple most strongly to the electronic system. For single-atom lead (Pb) contacts we show specific candidates for bistable switches, consisting of two similar atomic configurations with differing electric conductance. We identify vibrational modes that induce a transition between these configurations. Our results reveal a possible origin of bistable switching in atomic-size contacts through excitation of vibrations by inelastic electron scattering and underline the power of the combined DFT-NEGF approach and statistical mechanics analysis of a Langevin equation to overcome the time-scale gap between atomic motion and rare switching events, allowing for an efficient exploration of the contacts' configurational phase space. |
| title | Simulating bistable current-induced switching of metallic atomic contacts by electron-vibration scattering |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2303.03309 |