Unconventional crystal-field splitting in noncentrosymmetric BaTiO3 thin films

doi:10.1103/PhysRevMaterials.4.024413

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	Unconventional crystal-field splitting in noncentrosymmetric BaTiO3 thin films
	Song, Yang ; Liu, Xiaoran ; Wen, Fangdi ; Kareev, M.; Zhang, Ruyi ; Pei, Yujuan ; Bi, Jiachang ; Shafer, Padraic ; N'Diaye, Alpha T.; Arenholz, Elke
刊名	PHYSICAL REVIEW MATERIALS
	2020
卷号	4 期号:2
关键词	PHASE-TRANSITION FERROELECTRICITY POLARIZATION ORIGIN ENHANCEMENT DIAGRAM
DOI	10.1103/PhysRevMaterials.4.024413
英文摘要	Understanding the crystal-field splitting and orbital polarization in noncentrosymmetric systems such as ferroelectric materials is fundamentally important. In this study, taking BaTiO3 as a representative material, we investigate titanium crystal-field splitting and orbital polarization in noncentrosymmetric TiO6 octahedra with resonant x-ray linear dichroism at the Ti L-2,L-3 edge. The high-quality BaTiO3 thin films were deposited on DyScO3 (110) single crystal substrates in a layer-by-layer way by pulsed laser deposition. The reflection high-energy electron diffraction and element specific x-ray absorption spectroscopy were performed to characterize the structural and electronic properties of the films. In sharp contrast to conventional crystal-field splitting and orbital configuration (d(xz)/d(yz) < d(xy) < d(3z2-r2) < d(x2-y2) or d(xy) < d(xz)/d(yz) < d(x2-y2) < d(3z2-r2)) expected from compressive or tensile epitaxial strain, respectively, it is revealed that d(xz), d(yz), and d(xy) orbitals are nearly degenerate, whereas d(3z2-r2) and d(x2-y2) orbitals are split with an energy gap similar to 100 meV in the epitaxial BaTiO3 films. We find that the unexpected degenerate orbitals d(xz)/d(yz)/d(xy) result from the competition between the orbital splitting induced by epitaxial strain and that induced by polar distortions of BaTiO3 films. Our results provide a route to manipulate orbital degree of freedom by switching electric polarization in ferroelectric materials.
学科主题	Materials Science
内容类型	期刊论文
源URL	[http://ir.nimte.ac.cn/handle/174433/19955]
专题	2020专题
作者单位	1.Park, SY (corresponding author), Inst for Basic Sci Korea, Ctr Correlated Elect Syst, Seoul 08826, South Korea. 2.Park, SY (corresponding author), Seoul Natl Univ, Dept Phys & Astron, Seoul 08826, South Korea.
推荐引用方式 GB/T 7714	Song, Yang,Liu, Xiaoran,Wen, Fangdi,et al. Unconventional crystal-field splitting in noncentrosymmetric BaTiO3 thin films[J]. PHYSICAL REVIEW MATERIALS,2020,4(2).
APA	Song, Yang.,Liu, Xiaoran.,Wen, Fangdi.,Kareev, M..,Zhang, Ruyi.,...&Chakhalian, J..(2020).Unconventional crystal-field splitting in noncentrosymmetric BaTiO3 thin films.PHYSICAL REVIEW MATERIALS,4(2).
MLA	Song, Yang,et al."Unconventional crystal-field splitting in noncentrosymmetric BaTiO3 thin films".PHYSICAL REVIEW MATERIALS 4.2(2020).