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arXiv · 1610.07382

Temperature dependent giant resistance anomaly in LaAlO3/SrTiO3 nanostructures

M. Z. Minhas·A. Müller·F. Heyroth·H. H. Blaschek·G. Schmidt
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Abstract

The resistance of the electron gas at the interface between the two band insulators LaAlO3 (LAO) and SrTiO3 (STO) typically drops monotonically with temperature and R/T curves during cooling and warm-up look identical for large area structures. Here we show that if the LAO/STO is laterally restricted by nanopatterning the resistance exhibits a temperature anomaly. Warming up nanostructures from low temperatures leads to one or two pronounced resistance peaks between 50 and 100 K not observed for larger dimensions. During cool-down current filaments emerge at the domain walls that form during the well-known structural phase transition of the STO substrate. During warm-up the reverse phase transition can interrupt filaments before the sheet conductivity which dominates at higher temperature is reestablished. Due to the limited number of filaments in a nanostructure this process can result in a complete loss of conductance. As a consequence of these findings the transport physics extracted from experiments in small and large area LAO/STO structures may need to be reconsidered.

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M. Z. Minhas, A. Müller, F. Heyroth, H. H. Blaschek, G. Schmidt. 2016-10-24. Temperature dependent giant resistance anomaly in LaAlO3/SrTiO3 nanostructures. https://arxiv.org/abs/1610.07382

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