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Correlated Lattice Instability and Emergent Charged Domain Walls at Oxide Heterointerfaces
Author(s) -
Li Mengsha,
Huang Zhen,
Tang Chunhua,
Song Dongsheng,
Mishra Tara Prasad,
Ariando Ariando,
Venkatesan Thirumalai,
Li Changjian,
Pennycook Stephen J.
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201906655
Subject(s) - heterojunction , materials science , condensed matter physics , oxide , lattice (music) , instability , nanoscopic scale , chemical physics , nanotechnology , optoelectronics , physics , acoustics , mechanics , metallurgy
Charged domain walls provide possibilities in effectively manipulating electrons at nanoscales for developing next‐generation electronic devices. Here, using the atom‐resolved imaging and spectroscopy on LaAlO 3 /SrTiO 3 //NdGaO 3 heterostructures, the evolution of correlated lattice instability and charged domain walls is visualized crossing the conducting LaAlO 3 /SrTiO 3 heterointerface. When increasing the SrTiO 3 layer thickness to 20 unit cells and above, both LaAlO 3 and SrTiO 3 layers begin to exhibit measurable polar displacements to form a tail‐to‐tail charged domain wall at the LaAlO 3 /SrTiO 3 interface, resulting in the charged redistribution within the 2‐nm‐thick SrTiO 3 layer close to the LaAlO 3 /SrTiO 3 interface. The mobile charges in different heterostructures can be estimated by summing up Ti 3+ concentrations in the conducting channel, which is sandwiched by SrTiO 3 layers with interdiffusion and/or oxygen octahedral rotations. Those estimated mobile charges are quantitatively consistent with results from Hall measurements. The results not only shed light on complex oxide heterointerfaces, but also pave a new path to nanoscale charge engineering.