Accession Number : AD1050180


Title :   In-situ Charge Density Imaging of Metamaterials made with Switchable Two-dimensional Electron Gas at Oxide Heterointerfaces


Descriptive Note : Technical Report,13 Aug 2016,12 Aug 2017


Corporate Author : UNIVERSITY OF WISCONSIN SYSTEM MADISON United States


Personal Author(s) : EOM, CHANG BEOM ; Oh,Sang Ho


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1050180.pdf


Report Date : 28 Nov 2017


Pagination or Media Count : 10


Abstract : We have designed and grown LaAlO3/SrTiO3 oxide hetero-interfaces and switchable 2DEG by using pulsed laser deposition atomic within-situ reflection high-energy electron diffraction (RHEED). We have also demonstrated that the inline electron holography can directly visualize the 2DEG at the both (001) and (111) LAO/STO interface. Taking an example of 2DEGs forming at LAO/STO interfaces with different crystal symmetry, we have shown that the selective orbital occupation and spatial quantum confinement of 2DEGs can be resolved with sub-nm resolution using inline electron holography. For in-situ biasing experiments in TEM, we prepared two model heterostructures of switchable 2DEG systems and performed in-situ STEM HAADF imaging of the heterostructure taken under various DC biases. The electric potential images and profiles were obtained from the reconstructed phase of transmitted electron beam after calibrating local thickness of TEM sample.


Descriptors :   metamaterials , electron gas , voltage , electron density , charge density , charge carriers , thin films , quantum wells , phase transformations , nanotechnology , heterojunctions , electron diffraction


Subject Categories : Miscellaneous Materials


Distribution Statement : APPROVED FOR PUBLIC RELEASE