Large phonon drag thermopower boosted by massive electrons and phonon leaking in LaAlO3/LaNiO3/LaAlO3heterostructure

Masatoshi Kimura, Xinyi He, Takayoshi Katase, Terumasa Tadano, Jan M. Tomczak, Makoto Minohara, Ryotaro Aso, Hideto Yoshida, Keisuke Ide, Shigenori Ueda, Hidenori Hiramatsu, Hiroshi Kumigashira, Hideo Hosono, Toshio Kamiya

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5 Citations (Scopus)


An unusually large thermopower (S) enhancement is induced by heterostructuring thin films of the strongly correlated electron oxide LaNiO3. The phonon-drag effect, which is not observed in bulk LaNiO3, enhances S for thin films compressively strained by LaAlO3 substrates. By a reduction in the layer thickness down to three unit cells and subsequent LaAlO3 surface termination, a 10 times S enhancement over the bulk value is observed due to large phonon drag S (Sg), and the Sg contribution to the total S occurs over a much wider temperature range up to 220 K. The Sg enhancement originates from the coupling of lattice vibration to the d electrons with large effective mass in the compressively strained ultrathin LaNiO3, and the electron-phonon interaction is largely enhanced by the phonon leakage from the LaAlO3 substrate and the capping layer. The transition-metal oxide heterostructures emerge as a new playground to manipulate electronic and phononic properties in the quest for high-performance thermoelectrics.

Original languageEnglish
Pages (from-to)9240-9246
Number of pages7
JournalNano Letters
Issue number21
Publication statusPublished - Nov 10 2021

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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