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

Research output: Contribution to journalArticlepeer-review

Abstract

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
JournalNano Letters
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • Strongly correlated electron oxide
  • Thermoelectrics
  • Thin film heterostructure
  • Transition-metal oxide

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Fingerprint

Dive into the research topics of 'Large phonon drag thermopower boosted by massive electrons and phonon leaking in LaAlO<sub>3</sub>/LaNiO<sub>3</sub>/LaAlO<sub>3</sub>heterostructure'. Together they form a unique fingerprint.

Cite this