Modulation of Manganite Nanofilm Properties Mediated by Strong Influence of Strontium Titanate Excitons

Xinmao Yin, Chi Sin Tang, Muhammad Aziz Majidi, Peng Ren, Le Wang, Ping Yang, Caozheng Diao, Xiaojiang Yu, Mark B.H. Breese, Andrew T.S. Wee, Junling Wang, Andrivo Rusydi

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Hole-doped perovskite manganites have attracted much attention because of their unique optical, electronic, and magnetic properties induced by the interplay between spin, charge, orbital, and lattice degrees of freedom. Here, a comprehensive investigation of the optical, electronic, and magnetic properties of La 0.7 Sr 0.3 MnO 3 thin films on SrTiO 3 (LSMO/STO) and other substrates is conducted using a combination of temperature-dependent transport, spectroscopic ellipsometry, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. A significant difference in the optical property of LSMO/STO that occurs even in thick (87.2 nm) LSMO/STO from that of LSMO on other substrates is discovered. Several excitonic features are observed in thin film nanostructure LSMO/STO at -4 eV, which could be attributed to the formation of anomalous charged excitonic complexes. On the basis of the spectral weight transfer analysis, anomalous excitonic effects from STO strengthen the electronic correlation in LSMO films. This results in the occurrence of optical spectral changes related to the intrinsic Mott-Hubbard properties in manganites. We find that while lattice strain from the substrate influences the optical properties of the LSMO thin films, the coexistence of strong electron-electron (e-e) and electron-hole (e-h) interactions which leads to the resonant excitonic effects from the substrate plays a much more significant role. Our result shows that the onset of anomalous excitonic dynamics in manganite oxides may potentially generate new approaches in manipulating exciton-based optoelectronic applications.

Original languageEnglish
Pages (from-to)35563-35570
Number of pages8
JournalACS Applied Materials and Interfaces
Volume10
Issue number41
DOIs
Publication statusPublished - 17 Oct 2018

Keywords

  • electron-electron and electron-hole interactions
  • electronic and optical structures
  • manganite thin film
  • neutral and charged excitonic effects
  • spectroscopic ellipsometry

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