Laser molecular-beam epitaxy and second-order optical nonlinearity of BaTiO_3/SrTiO_3 superlattices  

作　　者：赵彤 陈凡 吕惠宾 杨国桢 陈正豪 

机构地区：[1]Laboratory of Optical Physics, Institute of Physics & Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China

出　　处：《Science China Mathematics》2000年第7期760-766,共7页中国科学：数学（英文版）

摘　　要：A series of c-axis oriented BaTiO3/SrTiO3 superlattices with the atomic-scale precision were epitaxially grown on single-crystal SrTiO3(100) substrates using laser molecular-beam epitaxy (LMBE). A periodic modulation of the intensity of reflection high-energy electron diffraction (RHEED) in BaTiO3 and SrTiO3 layers was observed and attributed to the lattice-misfit-induced periodic variation of the terrace density in film surface. The relationship between the second-order nonlinear optical sus-ceptibilities and the superlattice structure was systematically studied. The experimental and theoretical fitting results indicate that the second-order nonlinear optical susceptibilities of BaTiO3/SrTiO3 superlattices were greatly enhanced with the maximum value being more than one order of magnitude larger than that of bulk BaTiO3 crystal. The mechanism of the enhancement of the second-order optical non-linearity was discussed by taking into account the stress-induced lattice distortion and polarization enhancement.A series of c-axis oriented BaTiO3/SrTiO3 superlattices with the atomic-scale precision were epitaxially grown on single-crystal SrTiO3(100) substrates using laser molecular-beam epitaxy (LMBE). A periodic modulation of the intensity of reflection high-energy electron diffraction (RHEED) in BaTiO3 and SrTiO3 layers was observed and attributed to the lattice-misfit-induced periodic variation of the terrace density in film surface. The relationship between the second-order nonlinear optical sus-ceptibilities and the superlattice structure was systematically studied. The experimental and theoretical fitting results indicate that the second-order nonlinear optical susceptibilities of BaTiO3/SrTiO3 superlattices were greatly enhanced with the maximum value being more than one order of magnitude larger than that of bulk BaTiO3 crystal. The mechanism of the enhancement of the second-order optical non-linearity was discussed by taking into account the stress-induced lattice distortion and polarization

关 键 词：BaTiO3/SrTiO3 SUPERLATTICES LASER MOLECULAR-BEAM EPITAXY reflection high-energy electron diffrac-tion lattice MISFIT second-order optical nonlinearity. 

分 类 号：O782[理学—晶体学] O437[机械工程—光学工程]