Giant thermoelectric Seebeck coefficient of a two-dimensional electron gas in SrTiO3

Hiromichi Ohta, Sungwng Kim, Yoriko Mune, Teruyasu Mizoguchi, Kenji Nomura, Shingo Ohta, Takashi Nomura, Yuki Nakanishi, Yuichi Ikuhara, Masahiro Hirano, Hideo Hosono, Kunihito Koumoto

    Research output: Contribution to journalArticlepeer-review

    748 Citations (Scopus)


    Enhancement of the Seebeck coefficient (S) without reducing the electrical conductivity () is essential to realize practical thermoelectric materials exhibiting a dimensionless figure of merit (ZT≤S2T1) exceeding 2, where T is the absolute temperature and is the thermal conductivity. Here, we demonstrate that a high-density two-dimensional electron gas (2DEG) confined within a unit cell layer thickness in SrTiO"3 yields unusually large |S|, approximately five times larger than that of SrTiO"3 bulks, while maintaining a high 2DEG. In the best case, we observe |S| = 850 μ V K-1 and 2DEG≤1.4×103Scm1. In addition, by using the of bulk single-crystal SrTiO"3 at room temperature, we estimate ZT2.4 for the 2DEG, corresponding to ZT0.24 for a complete device having the 2DEG as the active region. The present approach using a 2DEG provides a new route to realize practical thermoelectric materials without the use of toxic heavy elements.

    Original languageEnglish
    Pages (from-to)129-134
    Number of pages6
    JournalNature Materials
    Issue number2
    Publication statusPublished - 2007 Feb

    ASJC Scopus subject areas

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

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