Faculté des sciences

Optical study of the free-carrier response of LaTiO₃/SrTiO₃ superlattices

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

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... Plus

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    Summary
    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.