TY - JOUR
T1 - Co valence transformation in isopolar LaCoO3/LaTiO3 perovskite heterostructures via interfacial engineering
AU - Araizi-Kanoutas, Georgios
AU - Geessinck, Jaap
AU - Gauquelin, Nicolas
AU - Smit, Steef
AU - Verbeek, Xanthe H.
AU - Mishra, Shrawan K.
AU - Bencok, Peter
AU - Schlueter, Christoph
AU - Lee, Tien-Lin
AU - Krishnan, Dileep
AU - Fatermans, Jarmo
AU - Verbeeck, Jo
AU - Rijnders, Guus
AU - Koster, Gertjan
AU - Golden, Mark S.
PY - 2020/2/10
Y1 - 2020/2/10
N2 - We report charge transfer up to a single electron per interfacial unit cell across nonpolar heterointerfaces from the Mott insulator LaTiO3 to the charge transfer insulator LaCoO3. In high-quality bi- and trilayer systems grown using pulsed laser deposition, soft x-ray absorption, dichroism, and scanning transmission electron microscopy-electron energy loss spectroscopy are used to probe the cobalt-3d electron count and provide an element-specific investigation of the magnetic properties. The experiments show the cobalt valence conversion is active within 3 unit cells of the heterointerface, and able to generate full conversion to 3d7 divalent Co, which displays a paramagnetic ground state. The number of LaTiO3/LaCoO3 interfaces, the thickness of an additional, electronically insulating “break” layer between the LaTiO3 and LaCoO3, and the LaCoO3 film thickness itself in trilayers provide a trio of control knobs for average charge of the cobalt ions in LaCoO3, illustrating the efficacy of O-2p band alignment as a guiding principle for property design in complex oxide heterointerfaces.
AB - We report charge transfer up to a single electron per interfacial unit cell across nonpolar heterointerfaces from the Mott insulator LaTiO3 to the charge transfer insulator LaCoO3. In high-quality bi- and trilayer systems grown using pulsed laser deposition, soft x-ray absorption, dichroism, and scanning transmission electron microscopy-electron energy loss spectroscopy are used to probe the cobalt-3d electron count and provide an element-specific investigation of the magnetic properties. The experiments show the cobalt valence conversion is active within 3 unit cells of the heterointerface, and able to generate full conversion to 3d7 divalent Co, which displays a paramagnetic ground state. The number of LaTiO3/LaCoO3 interfaces, the thickness of an additional, electronically insulating “break” layer between the LaTiO3 and LaCoO3, and the LaCoO3 film thickness itself in trilayers provide a trio of control knobs for average charge of the cobalt ions in LaCoO3, illustrating the efficacy of O-2p band alignment as a guiding principle for property design in complex oxide heterointerfaces.
U2 - 10.1103/PhysRevMaterials.4.026001
DO - 10.1103/PhysRevMaterials.4.026001
M3 - Article
SN - 2475-9953
VL - 4
JO - Physical Review Materials
JF - Physical Review Materials
IS - 2
M1 - 026001
ER -