Energy Level Alignment and Cation Charge States at the LaFeO3/LaMnO3 (001) Heterointerface. Issue 14 (26th April 2017)

• Record Type: Journal Article
• Authors: Smolin, Sergey Y.; Choquette, Amber K.; Wilks, Regan G.; Gauquelin, Nicolas; Félix, Roberto; Gerlach, Dominic; Ueda, Shigenori; Krick, Alex L.; Verbeeck, Johan; Bär, Marcus; Baxter, Jason B.; May, Steven J.
• Is Part Of: Advanced materials interfaces. Volume 4:Issue 14(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-04-26
• Subjects: band alignments -- interfaces -- perovskite oxides -- thin films -- valence states; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201700183
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract : The electronic properties of LaFeO3 /LaMnO3 epitaxial heterojunctions are investigated to determine the valence and conduction band offsets and the nominal Mn and Fe valence states at the interface. Studying a systematic series of (LaFeO3 ) n /(LaMnO3 ) m bilayers ( m ≈ 50) epitaxially grown in the (001) orientation using molecular beam epitaxy, layer‐resolved electron energy loss spectroscopy reveals a lack of significant interfacial charge transfer, with a nominal 3+ valence state observed for both Mn and Fe across the interface. Through a combination of variable angle spectroscopic ellipsometry and hard X‐ray photoelectron spectroscopy, type I energy level alignments are obtained at the LaFeO3 /LaMnO3 interface with positive valence and conduction band offsets of (1.20 ± 0.07) eV and (0.5–0.7 ± 0.3) eV, respectively, with minimal band bending. Variable temperature resistivity measurements reveal that the bilayers remain insulating and that the presence of the heterojunction does not result in a conducting interface. Abstract : The energy level alignments and the metal valences states are determined in LaFeO3 /LaMnO3 heterostructures grown by molecular beam epitaxy. Hard X‐ray photoemission spectroscopy derives the energy level alignment to be type I and electron energy loss spectroscopy reveals no significant charge transfer from the Mn to Fe cations.