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TT: Fachverband Tiefe Temperaturen

TT 66: Poster Session Transport

TT 66.4: Poster

Donnerstag, 19. März 2020, 15:00–19:00, P2/EG

Current induced switching in atomic copper junctions — •Patrick Haiber, Martin Prestel, David Weber, and Elke Scheer — Universität Konstanz, Konstanz, Deutschland

Electromigration is intensively studied in micron-size conductors as it is a major cause of failure in integrated circuits. Though, not much is known about the phenomenon when downscaling the sample size to the atomic size.

Here, we study current-induced switching of atomic-size contacts of Cu, a metal that is used as backend in integrated circuits. We present the fabrication of thin-film mechanically controlled break-junctions, using electron beam lithography on a phosphor bronze substrate and thin-flm (80 nm) evaporation. The transport experiments are performed at low temperature under cryogenic vacuum. The conductance histogram obtained from hundreds of conductance vs. distance traces shows a pronounced maximum at G = 1 G₀ as expected for monovalent metals [1] revealing the high sample quality.

The electromigration experiments are performed for contacts with conductance between 1 G₀ and 7 G₀ by applying an alternating bias current [2]. With this process, bistable as well as monostable conductance switching is observed. We discuss the statistical behavior of the switching phenomena as well as the dependence of the switching process on the ramping speed of the alternating current.

[1] Agraït et al., 2003, Phys. Rep. 377, 81-279

[2] Schirm et al., 2013, Nature Nanotech. 8, 645-648