In-plane quasi-single-domain BaTiO$_3$ via interfacial symmetry engineering
J. W. Lee, K. Eom, T. R. Paudel, B. Wang, H. Lu, H. Huyan, S. Lindemann, S. Ryu, H. Lee, T. H. Kim, Y. Yuan, J. A. Zorn, S. Lei, W. Gao, T. Tybell, V. Gopalan, … 展开作者
J. W. Lee, K. Eom, T. R. Paudel, B. Wang, H. Lu, H. Huyan, S. Lindemann, S. Ryu, H. Lee, T. H. Kim, Y. Yuan, J. A. Zorn, S. Lei, W. Gao, T. Tybell, V. Gopalan, X. Pan, A. Gruverman, L. Q. Chen, E. Y. Tsymbal, C. B. Eom
The control of the in-plane domain evolution in ferroelectric thin films is not only critical to understanding ferroelectric phenomena but also to enabling functional device fabrication. However, in-plane polarized ferroelectric thin films typically exhibit complicated multi-domain states, not desirable for optoelectronic device performance. Here we report a strategy combining interfacial symmetry engineering and anisotropic strain to design single-domain, in-plane polarized ferroelectric BaTiO$_3$ thin films. Theoretical calculations predict the key role of the BaTiO$_3$ / PrScO$_3$ (110)$_O$ substrate interfacial environment, where anisotropic strain, monoclinic distortions, and interfacial electrostatic potential stabilize a single-variant spontaneous polarization. A combination of scanning transmission electron microscopy, piezoresponse force microscopy, ferroelectric hysteresis loop measurements, and second harmonic generation measurements directly reveals the stabilization of the in-plane quasi-single-domain polarization state. This work offers design principles for engineering in-plane domains of ferroelectric oxide thin films, which is a prerequisite for high performance optoelectronic devices.
By means of ab initio calculations the possibilities of switchable spin-polarized two-dimensional electron gas (2DEG) at the interface of antiferromagnetic and ferroelectric perovskites, i.e., LaMnO3/BaTiO3 superlattice, were investigated. We demonstrate that at the heterostructure with TiO2/LaO interfacial layers the two-dimensional conducting state arises mainly localized within the interfacial MnO layer. The density of states at the Fermi-level can be tuned by ferroelectric polarization reversal. The conducting state coexists with magnetic one mainly arose from Mn atoms.
Controlling magnetic anisotropy by orbital magnetic moments related to interfacial strains has considerable potential for the development of future devices using spins and orbitals. For the fundamental physics, the relationship between strain and orbital magnetic moment is still unknown, because there are few tools to probe changes of orbital magnetic moment. In this study, we developed an electric-field- (E)-induced X-ray magnetic circular dichroism (EXMCD) technique to apply E to a ferroelectric BaTiO3 substrate. We reversibly tuned the interfacial lattice constants of Ni/Cu multilayers on B…
We use spin polarized low energy electron microscopy to investigate domain pattern transfer in a multiferroic heterostructure consisting of a $(111)$-oriented BaTiO$_{\mathrm{3}}$ substrate and an epitaxial Ni film. After in-situ thin film deposition and annealing through the ferroelectric phase transition, interfacial strain transfer from ferroelastic domains in the substrate and inverse magnetostriction in the magnetic thin film introduce a uniaxial in-plane magnetic anisotropy that rotates by $60^{\circ}$ between alternating stripe regions. We show that two types of magnetic domain wall can…
We report on domain pattern transfer from a ferroelectric BaTiO$_{\mathrm{3}}$ substrate with a $(111)$-orientation of the surface to an epitaxial Co film grown on a Pd buffer layer. Spatially modulated interfacial strain transfer from ferroelectric/ferroelastic domains and inverse magnetostriction in the ferromagnetic film induce stripe regions with a modulation of the in-plane uniaxial magnetic anisotropy direction. Using spin-polarized low energy electron microscopy, we observe the formation of two distinct anisotropy configurations between stripe regions. Moreover, through application of a…
Engineering Ferroelectric Phases in BaTiO$_3$ Films via Buffer-Layer Induced Misfit Strain Reversal
Southern Federal University（南联邦大学）；Federal Research Centre The Southern Scientific Centre of the Russian Academy of Sciences（俄罗斯科学院南方科学中心联邦研究中心）；Jožef Stefan Institute（约瑟夫斯蒂芬研究所）
The emerging interest in two-dimensional electron gases (2DEGs), formed at interfaces between two insulating oxide perovskites poses crucial fundamental question in view of future electronic devices. In the framework of density-functional theory, we investigate the possibility to control the characteristics of the 2DEG formed at the LaInO$_3$/BaSnO$_3$ interface by including a ferroelectric BaTiO$_3$ layer. To do so, we examine how the orientation of the ferroelectric polarization impacts density and confinement of the 2DEG. We find that aligning the ferroelectric polarization toward (outward)…
Fe doping into BaTiO3, stabilizes the paraelectric hexagonal phase in place of the ferroelectric tetragonal one [P. Pal et al. Phys. Rev. B, 101, 064409 (2020)]. We show that simultaneous doping of Bi along with Fe into BaTiO3 effectively enhances the magnetoelectric (ME) multiferroic response (both ferromagnetism and ferroelectricity) at room-temperature, through careful tuning of Fe valency along with the controlled-recovery of ferroelectric-tetragonal phase. We also report systematic increase in large dielectric constant values as well as reduction in loss tangent values with relatively mod…
Ferroelectric BaTiO3 films with large polarization have been integrated with Si(001) by pulsed laser deposition. High quality c-oriented epitaxial films are obtained in a substrate temperature range of about 300 deg C wide. The deposition temperature critically affects the growth kinetics and thermodynamics balance, resulting on a high impact in the strain of the BaTiO3 polar axis, which can exceed 2% in films thicker than 100 nm. The ferroelectric polarization scales with the strain and therefore deposition temperature can be used as an efficient tool to tailor ferroelectric polarization. The…
We propose energy band engineering to enhance tunneling electroresistance (TER) in ferroelectric tunnel junctions (FTJs). We predict that an ultrathin dielectric layer with a smaller band gap, embedded into a ferroelectric barrier layer, acts as a switch controlling high and low conductance states of an FTJ depending on polarization orientation. Using first-principles modeling based on density functional theory, we investigate this phenomenon for a prototypical SrRuO3/BaTiO3/SrRuO3 FTJ with a BaSnO3 monolayer embedded in the BaTiO3 barrier. We show that in such a composite-barrier FTJ, ferroel…
We report charge-transfer up to a single electron per interfacial unit cell across non-polar heterointerfaces from the Mott insulator LaTiO3 to the charge transfer insulator LaCoO3. In high-quality bi- and tri-layer systems grown using pulsed laser deposition, soft X-ray absorption, dichroism and STEM-EELS are used to probe the cobalt 3d-electron count and provide an element-specific investigation of the magnetic properties. The experiments prove a deterministically-tunable charge transfer process acting in the LaCoO3 within three unit cells of the heterointerface, able to generate full conver…
Interfacial Reconstructions and Engineering in III-V@II-VI Core-Shell Quantum Dots
BCMaterials, Basque Center for Materials, Applications, and Nanostructures, UPV/EHU（巴斯克材料、应用与纳米结构中心，巴斯克地区大学）；Istituto Italiano di Tecnologia（意大利理工大学）；Ghent University（根特大学）；Ikerbasque Basque Foundation for Science（伊克尔巴斯克科学基金会）
Charge-transfer interfaces between metal and redox arylamine molecular films: As probed with anode interfacial engineering approach in single-layer organic diodes
Due to high density of native defects, the prototypical topological insulator (TI), Bi$_2$Se$_3$, is naturally n-type. Although Bi$_2$Se$_3$ can be converted into p-type by substituting 2+ ions for Bi, only light elements such as Ca have been so far effective as the compensation dopant. Considering that strong spin-orbit coupling (SOC) is essential for the topological surface states, a light element is undesirable as a dopant, because it weakens the strength of SOC. In this sense, Pb, which is the heaviest 2+ ion, located right next to Bi in the periodic table, is the most ideal p-type dopant …
Domain-induced control of latent heat in freestanding BaTiO$_3$ membranes
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST（加泰罗尼亚纳米科学与纳米技术研究所）；Department of Physics, Facultat de Ciencies, Universitat Autonoma de Barcelona（巴塞罗那自治大学理学院物理系）
Solute decoration at grain boundaries (GB) leads to a number of phenomenon such as changes in interface structure,mobility,cohesion etc.Recent experimental investigations on interfacial segregation in steels are based on microstructural characterisation using two correlative methodologies, namely,Transmission Electron Microscopy-Atom Probe Tomography (APT) and Electron Backscatter Diffraction-APT.Considering the growing interest in this avenue,the present review is aimed at addressing the common adsorption isotherms used for quantifying interfacial segregation and providing an overview of the …
Ferroelectric--Superconducting Interaction in Epitaxial YBa2Cu3O7-δ/BaTiO3 Films
CSIRO Technology（澳大利亚联邦科学与工业研究组织技术部）；CSIRO Energy（澳大利亚联邦科学与工业研究组织能源部）；Australian Nuclear Science and Technology Organisation（澳大利亚核科学和技术组织）；School of Engineering, Macquarie University（麦考瑞大学工程学院）；School of Materials Science and Engineering, UNSW（新南威尔士大学材料科学与工程学院）
Tuning Cu/Diamond Interfacial Thermal Conductance via Nitrogen-Termination Engineering
Beijing Huairou Laboratory（北京怀柔实验室）；China Southern Power Grid Novel Electric Power System (BEIJING) Research Institute Co., Ltd（中国南方电网新型电力系统（北京）研究院有限公司）
Band structure engineering and interfacial buffer layers have been demonstrated as effective means to tune the Fermi level in topological insulators (TI). In particular, the charge compensated compound (BixSb1-x)2Te3 (BST) plays a critical role in the molecular beam epitaxy growth of magnetic TIs. Here we introduce a strategy of exploiting epitaxial Cr2O3 as a buffer layer and amorphous Cr2O3 as a capping layer in the growth of BST films. These films exhibit carrier density lower than 1012/cm2 over a wide range of Bi contents and higher mobility than BST films directly grown on Al2O3 substrate…
The interfacial Dyzaloshinskii-Moria interaction (DMI) helps to stabilize chiral domain walls and magnetic skyrmions, which will facilitate new magnetic memories and spintronics logic devices. The study of interfacial DMI in perpendicularly magnetized structurally asymmetric heavy metal (HM) / ferromagnetic (FM) multilayer systems is of high importance due to the formation of chiral magnetic textures in the presence of DMI. Here, we report the impact of the cobalt oxidation at the cobalt -aluminum oxide interface in Pt/Co/AlOx trilayer structure on the DMI by varying the post-growth annealing …
We show with first-principles molecular dynamics the persistence of intrinsic $\langle111\rangle$ Ti off-centerings for BaTiO$_3$ in its cubic paraelectric phase. Intriguingly, these are inconsistent with the Pm$\bar 3$m space group often used to atomistically model this phase using density functional theory or similar methods. Therefore we deploy a systematic symmetry analysis to construct representative structural models in the form of supercells that satisfy a desired point symmetry but are built from the combination of lower-symmetry primitive cells. We define as structural prototypes the …
In this work, we demonstrate a massive intrinsic exchange bias (3 kOe) in epitaxial CoFe2O4(111) thin films deposited on Al2O3(0001) substrates. This exchange bias is indicative of intrinsic exchange or a ferromagnetic material combined with an antiferromagnet. The analysis of structure, magnetism and electronic states corroborate that there is an interfacial layer CoO between the CoFe2O4(111) thin film and the Al2O3(0001) substrate. The power-law thickness dependence of the intrinsic exchange bias verifies its interfacial origin. This work suggests interfacial engineering can be an effective …
Controlling interfacial interactions in magnetic/topological insulator heterostructures is a major challenge for the emergence of novel spin-dependent electronic phenomena. As for any rational design of heterostructures that rely on proximity effects, one should ideally retain the overall properties of each component while tuning interactions at the interface. However, in most inorganic interfaces interactions are too strong, consequently perturbing, and even quenching, both the magnetic moment and the topological surface states at each side of the interface. Here we show that these properties…
Symmetry Rules for Cavity Materials Engineering with Linearly Polarized Vacuum Fields
Max Planck Institute for the Structure and Dynamics of Matter（马克斯·普朗克结构动力学研究所）；The Hamburg Centre for Ultrafast Imaging（汉堡超快成像中心）；Institute for Theory of Statistical Physics, RWTH Aachen University（亚琛工业大学统计物理理论研究所）；JARA Fundamentals of Future Information Technology（JARA未来信息技术基础）；Department of Electrophysics, National Yang Ming Chiao Tung University（国立阳明交通大学电波学系）；Initiative for Computational Catalysis, The Flatiron Institute, Simons Foundation（西蒙斯基金会平顿研究所计算催化倡议）
Contact resistance and interfacial engineering: Advances in high-performance 2D-TMD based devices
Shanghai University（上海大学）；Monash University（蒙纳士大学）；RMIT University（皇家墨尔本理工大学）；National University of Singapore（新加坡国立大学）；Queensland University of Technology（昆士兰科技大学）
High quality micro- and nano-mechanical resonators are widely used in sensing, communications and timing, and have future applications in quantum technologies and fundamental studies of quantum physics. Crystalline thin-films are particularly attractive for such resonators due to their prospects for high quality, intrinsic stress and yield strength, and low dissipation. However, when grown on a silicon substrate, interfacial defects arising from lattice mismatch with the substrate have been postulated to introduce additional dissipation. Here, we develop a new backside etching process for sing…
