Critical thickness for giant thermoelectric Seebeck coefficient of 2DEG confined in SrTiO3/SrTi0.8Nb0.2O3 superlattices

Hiromichi Ohta, Yoriko Mune, Kunihito Koumoto, Teruyasu Mizoguchi, Yuichi Ikuhara

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    31 Citations (Scopus)

    Abstract

    Seebeck coefficient (|S|) of two-dimensional electron gas (2DEG) confined within (SrTiO3)LB/(SrTi0.8Nb0.2O3)LW superlattices were measured at room temperature to clarify the critical thicknesses of barrier SrTiO3 (LB) and well SrTi0.8Nb0.2O3 (LW) for giant |S| [H. Ohta et al., Nat. Mater. 6, 129 (2007)]. The |S| values of the superlattices increased proportionally to LW- 1/2 due to increasing of the density of states near the conduction band edge (quantum size effect), and reached 300 μV K- 1 at LW = 1 unit cell SrTi0.8Nb0.2O3 (0.39 nm), which is ∼ 5 times larger than that of the SrTi0.8Nb0.2O3 bulk (60 μV K- 1). The critical thickness of LB and LW for giant |S| was clarified to be 16 unit cells (6.25 nm). The best thermoelectric performance can be obtained at (LB, LW) = (16, 1).

    Original languageEnglish
    Pages (from-to)5916-5920
    Number of pages5
    JournalThin Solid Films
    Volume516
    Issue number17
    DOIs
    Publication statusPublished - 2008 Jul 1

    Keywords

    • Seebeck coefficient
    • SrTiO
    • Superlattices
    • Thermoelectric energy conversion
    • Two-dimensional electron gas (2DEG)

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films
    • Metals and Alloys
    • Materials Chemistry

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