Publication Details

Meaney, S., Pan, A. V., Jones, A. & Fedoseev, S. A. (2019). Partial carrier freeze-out at the LaAlO3/SrTiO3 oxide interface. APL Materials, 7 (10), 101105-1-101105-5.


High quality robust two-dimensional electron gas (2DEG) LaAlO3/SrTiO3 (LAO/STO) interfaces are produced using pulsed laser deposition and an acid-free substrate Ti-Termination process, resulting in single unit cell terraces. Temperature dependent resistance measurements show two hysteresis anomalies around 80 K and 160 K. By using Hall measurements, we find an Arrhenius dependence in charge carrier density describing a partial carrier freeze-out below ∼80 K. We show that these two resistance anomalies are unrelated to the temperature dependence of the charge carrier density despite the tempting coincidence of the low temperature hysteresis feature and the freeze-out process. A two-carrier model is required to accurately estimate the activation energy of the thermally activated type charge carriers, which are found to be ∼5 to 7 meV. These results support the theory that oxygen vacancy defects contribute to the metallic conductivity at the 2DEG LAO/STO interface even for annealed samples.



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