Probing Nanoscale Ferroelectricity by Ultraviolet Raman Spectroscopy

D. A. TENNE; A. BRUCHHAUSEN; N. D. LANZILLOTTI-KIMURA; A. FAINSTEIN; R. S. KATIYAR; A. CANTARERO; A. SOUKIASSIAN; V. VAITHYANATHAN; J. H. HAENI; W. TIAN; D. G. SCHLOM; K. J. CHOI; D. M. KIM; C. B. EOM; H. P. SUN; X. Q. PAN; Y. L. LI; L. Q. CHEN; Q. X. JIA; S. M. NAKHMANSON; K. M. RABE; X. X. XI

SCIENCE

AAAS

Año: 2006 vol. 313 p. 1614 - 1614

0036-8075

We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (T$_c$) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO$_3$ layers in BaTiO$_3$/SrTiO$_3$ superlattices are not only ferroelectric (with Tc as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO$_3$ layers adjacent to them. T$_c$ was tuned by 500 kelvin by varying the thicknesses of the BaTiO$_3$ and SrTiO$_3$ layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.