Built-in and induced polarization across LaAlO$ 3$-SrTiO$ 3$ heterojunctions - Condensed Matter > Materials ScienceReport as inadecuate




Built-in and induced polarization across LaAlO$ 3$-SrTiO$ 3$ heterojunctions - Condensed Matter > Materials Science - Download this document for free, or read online. Document in PDF available to download.

Abstract: Ionic crystals terminated at oppositely charged polar surfaces are inherentlyunstable and expected to undergo surface reconstructions to maintainelectrostatic stability. Essentially, an electric field that arises betweenoppositely charged atomic planes gives rise to a built-in potential thatdiverges with thickness. In ultra thin film form however the polar crystals areexpected to remain stable without necessitating surface reconstructions, yetthe built-in potential has eluded observation. Here we present evidence of abuilt-in potential across polar \lao ~thin films grown on \sto ~substrates, asystem well known for the electron gas that forms at the interface. Byperforming electron tunneling measurements between the electron gas and ametallic gate on \lao ~we measure a built-in electric field across \lao ~of 93meV-\AA. Additionally, capacitance measurements reveal the presence of aninduced dipole moment near the interface in \sto, illuminating a uniqueproperty of \sto ~substrates. We forsee use of the ionic built-in potential asan additional tuning parameter in both existing and novel device architectures,especially as atomic control of oxide interfaces gains widespread momentum.



Author: Guneeta Singh-Bhalla, Christopher Bell, Jayakanth Ravichandran, Wolter Siemons, Yasuyuki Hikita, Sayeef Salahuddin, Arthur F. Heb

Source: https://arxiv.org/







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