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

doi:10.1038/nmat1821

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 journal › Article › peer-review

814 Citations (Scopus)

Abstract

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 language	English
Pages (from-to)	129-134
Number of pages	6
Journal	Nature Materials
Volume	6
Issue number	2
DOIs	https://doi.org/10.1038/nmat1821
Publication status	Published - 2007 Feb
Externally published	Yes

ASJC Scopus subject areas

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

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10.1038/nmat1821

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@article{500c8d2890cc4a4d9fa0a4b371f388d6,

title = "Giant thermoelectric Seebeck coefficient of a two-dimensional electron gas in SrTiO3",

abstract = "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.",

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

note = "Funding Information: This work was financially supported by the Industrial Technology Research Grant Program in 2005 from the New Energy and Industrial Technology Development Organization (NEDO) and a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (No. 18686054). Correspondence and requests for materials should be addressed to H.O.",

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doi = "10.1038/nmat1821",

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AU - Ohta, Hiromichi

AU - Kim, Sungwng

AU - Mune, Yoriko

AU - Mizoguchi, Teruyasu

AU - Nomura, Kenji

AU - Ohta, Shingo

AU - Nomura, Takashi

AU - Nakanishi, Yuki

AU - Ikuhara, Yuichi

AU - Hirano, Masahiro

AU - Hosono, Hideo

AU - Koumoto, Kunihito

N1 - Funding Information: This work was financially supported by the Industrial Technology Research Grant Program in 2005 from the New Energy and Industrial Technology Development Organization (NEDO) and a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (No. 18686054). Correspondence and requests for materials should be addressed to H.O.

PY - 2007/2

Y1 - 2007/2

N2 - 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.

AB - 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.

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

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