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HL: Fachverband Halbleiterphysik
HL 52: Oxide Semiconductors II
HL 52.5: Vortrag
Donnerstag, 20. März 2025, 16:15–16:30, H14
Unraveling the mechanism of resistive switching in titanate-based perovskites — Wahib Aggoune1,2, •Parrydeep Kaur Sachdeva1, and Matthias Scheffler1 — 1The NOMAD Laboratory at Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany — 2Physics Department and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
Memristors capable of switching between high and low resistance states while retaining memory, hold promise for non-volatile memory. A recent fascinating experimental work observed high resistive switching (RS) in off-stoichiometric paraelectric titanate-based perovskites ATiO3 (A=Sr, Ca) [1]. It suggests that RS is driven by defects, though their exact role remains unclear. Here, we investigate the defects behavior using density functional theory. Under the experimental growth conditions, the complex defect (Ti-interstitial with A-vacancies) is thermodynamically stable, pinning the Fermi level close the conduction band. Remarkably, the off-center shift of the interstitial atom induces a local polarization and gives rise to localized mid-gap states. Switching between the equivalent off-center sites faces energy barriers of 0.1–0.8 eV, depending on the pathway. This switches both polarization direction and the defect charge distribution. Therefore, upon applying a voltage, the overall polarization driven by the local shifts of the defects can be switched. As this also redistributes the defect charge states, it switches the resistance state. Our findings provide insights into the origin of RS toward memristor development.
[1] A. Baki, et al., Sci. Rep., 11, 7497 (2021).
Keywords: Density funtional theory; Defects; Memristor