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

doi:10.1016/j.tsf.2007.10.034

Critical thickness for giant thermoelectric Seebeck coefficient of 2DEG confined in SrTiO₃/SrTi_0.8Nb_0.2O₃ superlattices

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

Research output: Contribution to journal › Article › peer-review

31 Citations (Scopus)

Abstract

Seebeck coefficient (|S|) of two-dimensional electron gas (2DEG) confined within (SrTiO₃)_LB/(SrTi_0.8Nb_0.2O₃)_LW superlattices were measured at room temperature to clarify the critical thicknesses of barrier SrTiO₃ (L_B) and well SrTi_0.8Nb_0.2O₃ (L_W) for giant |S| [H. Ohta et al., Nat. Mater. 6, 129 (2007)]. The |S| values of the superlattices increased proportionally to L_W^{- 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 L_W = 1 unit cell SrTi_0.8Nb_0.2O₃ (0.39 nm), which is ∼ 5 times larger than that of the SrTi_0.8Nb_0.2O₃ bulk (60 μV K^{- 1}). The critical thickness of L_B and L_W for giant |S| was clarified to be 16 unit cells (6.25 nm). The best thermoelectric performance can be obtained at (L_B, L_W) = (16, 1).

Original language	English
Pages (from-to)	5916-5920
Number of pages	5
Journal	Thin Solid Films
Volume	516
Issue number	17
DOIs	https://doi.org/10.1016/j.tsf.2007.10.034
Publication status	Published - 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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@article{06aaf91da6c848d7a5e91800227f178c,

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

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).",

keywords = "Seebeck coefficient, SrTiO, Superlattices, Thermoelectric energy conversion, Two-dimensional electron gas (2DEG)",

author = "Hiromichi Ohta and Yoriko Mune and Kunihito Koumoto and Teruyasu Mizoguchi and Yuichi Ikuhara",

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 Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (no. 18686054).",

year = "2008",

month = jul,

day = "1",

doi = "10.1016/j.tsf.2007.10.034",

language = "English",

volume = "516",

pages = "5916--5920",

journal = "Thin Solid Films",

issn = "0040-6090",

publisher = "Elsevier",

number = "17",

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TY - JOUR

T1 - Critical thickness for giant thermoelectric Seebeck coefficient of 2DEG confined in SrTiO3/SrTi0.8Nb0.2O3 superlattices

AU - Ohta, Hiromichi

AU - Mune, Yoriko

AU - Koumoto, Kunihito

AU - Mizoguchi, Teruyasu

AU - Ikuhara, Yuichi

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 Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (no. 18686054).

PY - 2008/7/1

Y1 - 2008/7/1

N2 - 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).

AB - 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).

KW - Seebeck coefficient

KW - SrTiO

KW - Superlattices

KW - Thermoelectric energy conversion

KW - Two-dimensional electron gas (2DEG)

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