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2023-01-16T03:55:49Z
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Enhanced Seebeck coefficient of quantum-confined electrons in SrTiO_3/SrTi_0.8Nb_0.2O_3 superlattices
Mune, Yoriko
Ohta, Hiromichi
Koumoto, Kunihito
Mizoguchi, Teruyasu
Ikuhara, Yuichi
open access
Copyright (2007) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
We report two-dimensional Seebeck coefficients (|S|_2D) of [(SrTiO_3)x/(SrTi_0.8Nb_0.2O_3)y]_20 (x=1–60, y=1–20) superlattices, which were grown on the (100) face of insulating LaAlO_3 substrates to clarify the origin of the giant |S|_2D values of the SrTiO_3 superlattices [H. Ohta et al., Nat. Mater. 6, 129 (2007)]. The |S|_2D values of the [(SrTiO_3)_17/(SrTi_0.8Nb_0.2O_3)y]_20 superlattices increased proportionally to y^{−0.5} and reached 320µVK^{−1} (y=1), which is approximately five times larger than that of the SrTi_0.8Nb_0.2O_3 bulk (|S|_3D=61µVK^{−1}). The slope of the log|S|_2D-log y plots was −0.5, proving that the density of states in the ground state for SrTiO_3 increases inversely proportionally to y. The critical barrier thickness for quantum electron confinement was also clarified to be 6.25nm (16 unit cells of SrTiO_3).
American Institite of Physics
2007-11-08
eng
journal article
VoR
http://hdl.handle.net/2237/11980
https://nagoya.repo.nii.ac.jp/records/10162
https://doi.org/10.1063/1.2809364
0003-6951
APPLIED PHYSICS LETTERS
91
192105
192105
https://nagoya.repo.nii.ac.jp/record/10162/files/ApplPhysLett_91_192105.pdf
application/pdf
455.3 kB
2018-02-20