Synthesis of metastable Ruddlesden–Popper titanates, (ATiO3)nAO, with n ≥ 20 by molecular-beam epitaxy
Matthew R. Barone,
Myoungho Jeong,
Nicholas Parker,
Jiaxin Sun,
Dmitri A. Tenne,
Kiyoung Lee,
Darrell G. Schlom
Affiliations
Matthew R. Barone
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
Myoungho Jeong
Nano Electronics Laboratory, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, South Korea
Nicholas Parker
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
Jiaxin Sun
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
Dmitri A. Tenne
Department of Physics, Boise State University, Boise, Idaho 83725-1570, USA
Kiyoung Lee
Nano Electronics Laboratory, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, South Korea
Darrell G. Schlom
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
We outline a method to synthesize (ATiO3)nAO Ruddlesden–Popper phases with high-n, where the A-site is a mixture of barium and strontium, by molecular-beam epitaxy. The precision and consistency of the method described is demonstrated by the growth of an unprecedented (SrTiO3)50SrO epitaxial film. We proceed to investigate barium incorporation into the Ruddlesden–Popper structure, which is limited to a few percent in bulk, and we find that the amount of barium that can be incorporated depends on both the substrate temperature and the strain state of the film. At the optimal growth temperature, we demonstrate that as much as 33% barium can homogeneously populate the A-site when films are grown on SrTiO3 (001) substrates, whereas up to 60% barium can be accommodated in films grown on TbScO3 (110) substrates, which we attribute to the difference in strain. This detailed synthetic study of high n, metastable Ruddlesden–Popper phases is pertinent to a variety of fields from quantum materials to tunable dielectrics.
