Optical Study of the Free Carrier Response of LaTiO₃/SrTiO₃ Superlattices

Journal Article · Mon Jan 01 00:00:00 EST 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.99.266801· OSTI ID:930911

Seo, S. S. A. ^[1]; Choi, W. S. ^[1]; Lee, Ho Nyung ^[2]; Yu, L. ^[3]; Kim, K. W. ^[3]; Bernhard, C ^[3]; Noh, Tae Won ^[1]

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1. Seoul National University
2. ORNL
3. University of Fribourg

We used infrared spectroscopic ellipsometry to investigate the electronic properties of LaTiO{sub 3}/SrTiO{sub 3} 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 {approx}3x10{sup 14}cm{sup -2}. This is probably due to the leakage of d electrons at interfaces from the Mott insulator LaTiO{sub 3}to the band insulator SrTiO{sub 3}. We observed a carrier relaxation time {approx}35fs and mobility {approx}35cm2V-1s-1 at 10 K, and an unusual temperature dependence of carrier density that was attributed to the dielectric screening of quantum paraelectric SrTiO{sub 3}.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 930911
• Journal Information: Physical Review Letters, Vol. 99; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARRIER DENSITY
DIELECTRIC MATERIALS
ELECTRONS
ELLIPSOMETRY
PERIODICITY
RELAXATION TIME
SUPERLATTICES
TEMPERATURE DEPENDENCE
THICKNESS