Tenne D A, Bruchhausen A, Lanzillotti-Kimura N D, Fainstein A, Katiyar R S, Cantarero A, Soukiassian A, Vaithyanathan V, Haeni J H, Tian W, Schlom D G, Choi K J, Kim D M, Eom C B, Sun H P, Pan X Q, Li Y L, Chen L Q, Jia Q X, Nakhmanson S M, Rabe K M, Xi X X
Department of Physics, Pennsylvania State University, University Park, PA 16802, USA.
Science. 2006 Sep 15;313(5793):1614-6. doi: 10.1126/science.1130306.
We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (Tc) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO3 layers in BaTiO3/SrTiO3 superlattices are not only ferroelectric (with Tc as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO3 layers adjacent to them. Tc was tuned by approximately 500 kelvin by varying the thicknesses of the BaTiO3 and SrTiO3 layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.
我们证明了紫外拉曼光谱是一种测量铁电超薄膜和超晶格中转变温度（Tc）的有效技术。我们表明，BaTiO3/SrTiO3超晶格中一个晶胞厚的BaTiO3层不仅是铁电的（Tc高达250开尔文），而且还会极化与其相邻的量子顺电SrTiO3层。通过改变BaTiO3和SrTiO3层的厚度，Tc被调节了约500开尔文，揭示了电和机械边界条件对纳米级铁电性的重要作用。
