Surface step terrace tuned microstructures and dielectric properties of highly epitaxial CaCu3Ti4O12 thin films on vicinal LaAlO3 substrates

Guang Yao; Min Gao; Yanda Ji; Weizheng Liang; Lei Gao; Shengliang Zheng; You Wang; Bin Pang; Y B Chen; Huizhong Zeng; Handong Li; Zhiming Wang; Jingsong Liu; Chonglin Chen; Yuan Lin

doi:10.1038/srep34683

Surface step terrace tuned microstructures and dielectric properties of highly epitaxial CaCu₃Ti₄O₁₂ thin films on vicinal LaAlO₃ substrates

Sci Rep. 2016 Oct 5:6:34683. doi: 10.1038/srep34683.

Authors

Guang Yao¹, Min Gao¹, Yanda Ji¹, Weizheng Liang¹, Lei Gao¹, Shengliang Zheng², You Wang², Bin Pang³, Y B Chen⁴, Huizhong Zeng¹, Handong Li¹, Zhiming Wang¹, Jingsong Liu⁵, Chonglin Chen^{6

7}, Yuan Lin¹

Affiliations

¹ State Key Laboratory of Electronic Thin films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, P. R. China.
² Department of Materials Physics and Chemistry, Harbin Institute of Technology, Harbin 150001, P. R. China.
³ National Laboratory of Solid State Microstructures &Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 China.
⁴ National Laboratory of Solid State Microstructures &Department of Physics, Nanjing University, Nanjing 210093 China.
⁵ State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010, P. R. China.
⁶ Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, USA.
⁷ Department of Physics and the Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, USA.

Abstract

Controllable interfacial strain can manipulate the physical properties of epitaxial films and help understand the physical nature of the correlation between the properties and the atomic microstructures. By using a proper design of vicinal single-crystal substrate, the interface strain in epitaxial thin films can be well controlled by adjusting the miscut angle via a surface-step-terrace matching growth mode. Here, we demonstrate that LaAlO₃ (LAO) substrates with various miscut angles of 1.0°, 2.75°, and 5.0° were used to tune the dielectric properties of epitaxial CaCu₃Ti₄O₁₂ (CCTO) thin films. A model of coexistent compressive and tensile strained domains is proposed to understand the epitaxial nature. Our findings on the self-tuning of the compressive and tensile strained domain ratio along the interface depending on the miscut angle and the stress relaxation mechanism under this growth mode will open a new avenue to achieve CCTO films with high dielectric constant and low dielectric loss, which is critical for the design and integration of advanced heterostructures for high performance capacitance device applications.

Publication types

Research Support, Non-U.S. Gov't