Interface Control of Ferroelectricity in an SrRuO3 /BaTiO3 /SrRuO3 Capacitor and its Critical Thickness

Yeong Jae Shin; Yoonkoo Kim; Sung-Jin Kang; Ho-Hyun Nahm; Pattukkannu Murugavel; Jeong Rae Kim; Myung Rae Cho; Lingfei Wang; Sang Mo Yang; Jong-Gul Yoon; Jin-Seok Chung; Miyoung Kim; Hua Zhou; Seo Hyoung Chang; Tae Won Noh

doi:10.1002/adma.201602795

Interface Control of Ferroelectricity in an SrRuO₃ /BaTiO₃ /SrRuO₃ Capacitor and its Critical Thickness

Adv Mater. 2017 May;29(19). doi: 10.1002/adma.201602795. Epub 2017 Mar 3.

Authors

Yeong Jae Shin^{1

2}, Yoonkoo Kim³, Sung-Jin Kang^{1

2}, Ho-Hyun Nahm^{1

2}, Pattukkannu Murugavel⁴, Jeong Rae Kim^{1

2}, Myung Rae Cho^{1

2}, Lingfei Wang^{1

2}, Sang Mo Yang⁵, Jong-Gul Yoon⁶, Jin-Seok Chung⁷, Miyoung Kim³, Hua Zhou⁸, Seo Hyoung Chang⁹, Tae Won Noh^{1

2}

Affiliations

¹ Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea.
² Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea.
³ Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea.
⁴ Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India.
⁵ Department of Physics, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
⁶ Department of Physics, University of Suwon, Hwaseong, Gyunggi-do, 18323, Republic of Korea.
⁷ Department of Physics, Soongsil University, Seoul, 06978, Republic of Korea.
⁸ Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA.
⁹ Department of Physics, Pukyong National University, Busan, 48513, Republic of Korea.

PMID: 28256752
DOI: 10.1002/adma.201602795

Abstract

The atomic-scale synthesis of artificial oxide heterostructures offers new opportunities to create novel states that do not occur in nature. The main challenge related to synthesizing these structures is obtaining atomically sharp interfaces with designed termination sequences. In this study, it is demonstrated that the oxygen pressure (PO2) during growth plays an important role in controlling the interfacial terminations of SrRuO₃ /BaTiO₃ /SrRuO₃ (SRO/BTO/SRO) ferroelectric (FE) capacitors. The SRO/BTO/SRO heterostructures are grown by a pulsed laser deposition method. The top SRO/BTO interface, grown at high PO2 (around 150 mTorr), usually exhibits a mixture of RuO₂ -BaO and SrO-TiO₂ terminations. By reducing PO2, the authors obtain atomically sharp SRO/BTO top interfaces with uniform SrO-TiO₂ termination. Using capacitor devices with symmetric and uniform interfacial termination, it is demonstrated for the first time that the FE critical thickness can reach the theoretical limit of 3.5 unit cells.

Keywords: BaTiO3; ferroelectric critical thickness; ferroelectricity; interface engineering.