Domain matching epitaxy of BaBiO3 on SrTiO3 with structurally modified interface

The electronic structures of BaBiO3 (BBO) thin films grown on SrTiO3 substrates are found to be thickness dependent. The origin of this behavior remains under debate and has been suggested to be attributed to the structural and compositional modifications at the BBO/SrTiO3 interface during the first stage of film growth. Though a wetting layer with thickness of ≈1 nm has been experimentally identified at the interface, details on the microstructures of such a layer and their effect on the subsequent film growth are lacking so far, particularly at the atomic scale. Herein, atomic‐resolution scanning transmission electron microscopy is used to study the interface structure of a 30 nm‐thick BBO film grown on an Nb‐doped SrTiO3 (STO) substrate through domain matching epitaxy. An interfacial δ‐Bi2O3 (BO)‐like phase with fluorite structure is identified, showing a layer‐by‐layer spacing of ≈3.2 Å along the growth direction. The orientation relationship between the BO‐like phase and surrounding perovskites (P) is found to be <001>BO||<001>P and <110>BO||<100>P. The presence of the BO‐like phase results in two types of interfaces, i.e., a coherent BO/STO and a semicoherent BBO/BO interface. Thickness variations are observed in the BO‐like layer, resulting in the formation of antiphase domains in the BBO films.

“…As the STO substrate is thought to be rigid, the reduction in n therefore necessitates an in‐plane lattice expansion of the BBO film from the bulk value to ≈4.39 Å (according to

\sqrt{2}

supporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Atomic‐Scale Interface Structure in Domain Matching Epitaxial BaBiO₃ Thin Films Grown on SrTiO₃ Substrates

Jin

Zapf

Stübinger

et al. 2020

“…The anti‐phase boundary is caused by the reconstruction layer at the STO/BBO interface, BBO no longer has a single terminated nucleation side. A similar phenomena in epitaxial BBO films is discussed in the recent article by Zapf et al…”

Section: The Four Possible Scenarios Of the Y–bi–o Systemsupporting

confidence: 64%

Stabilization of the Perovskite Phase in the Y–Bi–O System By Using a BaBiO₃ Buffer Layer

Bouwmeester

Hond

Gauquelin³

et al. 2019

A topological insulating phase has theoretically been predicted for the thermodynamically unstable perovskite phase of YBiO 3 . Here, it is shown that the crystal structure of the Y-Bi-O system can be controlled by using a BaBiO 3 buffer layer. The BaBiO 3 film overcomes the large lattice mismatch of 12% with the SrTiO 3 substrate by forming a rocksalt structure in between the two perovskite structures. Depositing an YBiO 3 film directly on a SrTiO 3 substrate gives a fluorite structure. However, when the Y-Bi-O system is deposited on top of the buffer layer with the correct crystal phase and comparable lattice constant, a single oriented perovskite structure with the expected lattice constants is observed.Topological materials are at the focus of a relatively young field in material science, aiming to find both new topological materials as well as discovering novel applications for this new class of matter. The most prominent phenomena that emerge in topological materials include a chiral spin structure and topologically protected surface states. [1,2] The spin-momentum locking makes topological matter interesting for spintronic applications [1,3,4] and possibly quantum computation. [5] Therefore, global research is conducted towards further developing known topological materials and trying to find new compounds that have a non-trivial topology in their band structure.So far, only a handful of materials have been identified as topological insulators (TIs). Within a year after the theoretical prediction of Bernevig et al., [1] König et al. [3] observed the quantum spin Hall state in CdTe/HgTe/CdTe quantum wells À the first system known with a non-trivial band structure. Bi 1-x Sb x was the first three-dimensional TI that was experimentally observed, [6] followed by Bi 2 Se 3 , [7] and Bi 2 Te 3 . [4] The relatively heavy bismuth gives rise to strong spin-orbit coupling (SOC) effects, which in turn results in a band inversion at an odd

Heteroepitaxial Hexagonal (00.1) CuFeO₂ Thin Film Grown on Cubic (001) SrTiO₃ Substrate Through Translational and Rotational Domain Matching

Luo

Harrington

et al. 2021

Heteroepitaxy of complex oxide thin films is a significant challenge when a large mismatch in the lattice parameters (>8%) and difference in the crystallographic symmetry coexist between the film and substrate. Herein, the heteroepitaxial growth of a hexagonal delafossite CuFeO2 thin film with (00.1) orientation on a cubic perovskite (001) SrTiO3 substrate through translational and rotational domain matching epitaxy is reported. The rotational in‐plane domain orientation relationships are CuFeO2 [11.0]//SrTiO3 [110] and CuFeO2 [2.0]//SrTiO3 [110] with about 10% in‐plane lattice mismatch. The 14.8 nm‐thick (00.1) CuFeO2 thin film shows high‐crystalline quality with a full width at half maximum of rocking curve of about 0.24° and exhibits a possible indirect optical bandgap of 1.43 eV or direct optical bandgap of 1.94 eV. Herein, not only a model system demonstrating translational and rotational domain matching heteroepitaxy of complex oxides is reported, but also a way to thin‐film heterostructures integrating hexagonal delafossite with cubic perovskite materials for functional oxide devices is opened.