Optical Study of the Free-Carrier Response of ${\mathrm{LaTiO}}_{3}/{\mathrm{SrTiO}}_{3}$ Superlattices

Seo, S. S. A.; Choi, W. S.; Lee, H. N.; Yu, Li; Kim, Kyung Wan; Bernhard, Christian; Noh, T. W.

doi:10.1103/PhysRevLett.99.266801

Back

Journal article

Optical Study of the Free-Carrier Response of ${\mathrm{LaTiO}}_{3}/{\mathrm{SrTiO}}_{3}$ Superlattices

Seo, S. S. A. ReCOE & FPRD, Department of Physics and Astronomy, Seoul National University, Korea
Choi, W. S. ReCOE & FPRD, Department of Physics and Astronomy, Seoul National University, Korea
Lee, H. N. Materials Science and Technology Division, Oak Ridge National Laboratory, USA
Yu, Li Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Kim, Kyung Wan Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Bernhard, Christian Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Noh, T. W. ReCOE & FPRD, Department of Physics and Astronomy, Seoul National University, Korea

26.12.2007

Published in:

Physical Review Letters. - 2007, vol. 99, no. 26, p. 266801

English We used infrared spectroscopic ellipsometry to investigate the electronic properties of LaTiO₃/SrTiO₃ superlattices (SLs). Our results indicated that, independent of the SL periodicity and individual layer thickness, the SLs exhibited a Drude metallic response with sheet carrier density per interface ≈3×10¹⁴ cm⁻². This is probably due to the leakage of d electrons at interfaces from the Mott insulator LaTiO₃ to the band insulator SrTiO₃. We observed a carrier relaxation time ≈35 fs and mobility ≈35 cm² V⁻¹ s⁻¹ at 10 K, and an unusual temperature dependence of carrier density that was attributed to the dielectric screening of quantum paraelectric SrTiO₃.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

Language