Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session G64: Strong Correlation, Competing Phases, and Spin-Orbit Interactions in Complex Oxide HeterostructuresFocus
|
Hide Abstracts |
Sponsoring Units: DMP Chair: Alexandru Bogdan Georgescu, Simons Foundation Room: Mile High Ballroom 4E |
Tuesday, March 3, 2020 11:15AM - 11:27AM |
G64.00001: Electronic reconstruction at the interface of SrIrO3 and SrRuO3 Jocienne Nelson, Nathaniel Schreiber, Alexandru Bogdan Georgescu, Berit Goodge, Cyrus Zeledon, Lena Fitting Kourkoutis, Andrew Millis, Antoine Georges, Darrell Schlom, Kyle M Shen The interface between SrIrO3 and SrRuO3 has been the focus of much attention due to reports of emergent phenomena including the topological Hall effect and magnetic skyrmions. However, due to the presence of electron correlations, strong spin orbit interactions, and ferromagnetism, the electronic structure of the interface is challenging to predict and understand. Here we employ a combination of oxide molecular-beam epitaxy, in situ angle-resolved photoemission spectroscopy, scanning transmission electron microscopy, and density functional theory to investigate heterostructures of SrIrO3 / SrRuO3. We perform a systematic investigation of the electronic structure of (SrIrO3)n/ (SrRuO3)20, spanning n = 1 to 10 to investigate the electronic reconstruction as a function of distance from the interface. |
Tuesday, March 3, 2020 11:27AM - 12:03PM |
G64.00002: Breaking Symmetries to Create a Robust Room-Temperature Ferrimagnetic Ferroelectric in LuFeO3/CoFe2O4 Superlattices Invited Speaker: Darrell Schlom Materials that exhibit simultaneous order in their electric and magnetic ground states hold tremendous promise for use in next-generation, low-power memory and logic devices in which electric fields control magnetism. Such materials are, however, rare as a consequence of the competing requirements for ferroelectricity and magnetism, and until recently BiFeO3 was the only material with this functionality at room temperature. Interface materials are a way to overcome these competing requirements, as was recently demonstrated for (LuFeO3)m/(LuFe2O4)1 superlattices [J.A. Mundy et al. Nature 537 (2016) 523–527.]. The rumpling imposed by the geometric ferroelectric hexagonal LuFeO3 imposes a local distortion on the neighboring LuFe2O4—a distortion that removes the mirror symmetry that the LuFe2O4 layers would otherwise have. This breaking of symmetry enables the LuFe2O4 to become simultaneously ferrimagnetic and ferroelectric. This rumpling is distinct from strain engineering because no macroscopic strain is involved. In this presentation we extend this atomically engineered design methodology to LuFeO3/CoFe2O4 superlattices producing a robust ground state that is simultaneously ferroelectric and ferrimagnetic at temperatures well above room temperature. |
Tuesday, March 3, 2020 12:03PM - 12:15PM |
G64.00003: Metal-insulator transition and charge transfer in complex oxide heterostructures from DFT+DMFT Sophie Beck, Claude Ederer We study the interplay between several control mechanisms on the emerging functionalities of complex oxide thin films and heterostructures composed of different early transition metal oxides, including correlated metals, Mott insulators and band insulators, using a combination of density functional theory (DFT) and dynamical mean-field theory (DMFT). |
Tuesday, March 3, 2020 12:15PM - 12:27PM |
G64.00004: Long-range magnetic reconstruction of Jeff = 1/2 pseudospins in Sr2IrO4 via 5d-4d interfacial interactions with Sr2RuO4 Maryam Souri, Christopher Dietl, Ekaterina Paerschke, Gabriel A Calderon Ortiz, Sujan Shrestha, Jinwoo Hwang, Gang Cao, Jong Woo Kim, Jung Ho Kim, Ambrose Seo Sr2IrO4 has attracted attention for its relativistic Mott insulating states originating from strong spin-orbit coupling (SOC) and electron-correlation. The strong SOC in iridates entangles the magnetic moments and orbital degrees of freedom, making the system sensitive to external stimuli. |
Tuesday, March 3, 2020 12:27PM - 12:39PM |
G64.00005: Effect of Misfit Dislocation in SrIrO3 heterostructures Zhen Wang, David A Howe, Prahald Siwakoti, Mohammad Saghayezhian, Yimei Zhu, E Ward Plummer, Jiandi Zhang Iridates benefit from a large spin-orbit coupling where the Ir-O bond geometry strongly impacts both electronic and magnetic properties leading to topologically non-trivial spin textures. The coupled spin and charge combined with interface engineering provides a unique opportunity to harvest the expected magnetoelectric coupling in BaTiO3 (BTO)/ SrIrO3 (SIO) superlattices where induced non-centrosymmetricity is present. A clear picture of the microstructures at interface is required for understanding the intrinsic structure-property relationship. By using scanning/transmission electron microscopy, we studied the structural feature of the BTO/SIO superlattices on SrTiO3 (001) substrate. Misfit dislocations are found in the superlattices to compensate the large lattice parameter and octahedra rotation mismatch between BTO and SIO. Due to the gradual relaxation of mismatch strain, the density of the misfit dislocation changes as a function of the superlattice thickness, and it almost disappears under a certain thickness. Moreover, the effect of the misfit dislocation on the magnetic property will also be discussed. |
Tuesday, March 3, 2020 12:39PM - 12:51PM |
G64.00006: Nanophotonic Engineering of Reconfigurable Vanadium Dioxide Phases Dustin Schrecongost, Yinxiao Xiang, Hai-Tian Zhang, Roman Engel-Herbert, Cheng Cen The metal-insulator transition in VO2 has extended applications in active optoelectronics and metasurfaces. Recently we have shown that by using scanning probe lithography techniques, various insulating and metallic VO2 phases can be manipulated on-demand in nanoscale. Here we study the plasmonic properties of a room-temperature monoclinic metal phase of VO2 and explore planar structure designs for desired optical functionalities. As a proof of concept, reconfigurable optical polarizers and plasmonic spatial modulators have been demonstrated. These results showcase the potential of building programmable nanophotonic devices on a monolithic correlated material platform. |
Tuesday, March 3, 2020 12:51PM - 1:03PM |
G64.00007: Characteristic Lengths of Interlayer Charge-Transfer in Correlated Oxide Heterostructures Ganesh Ji Omar, Ariando Ariando Electronic devices in the form of high mobility conducting channel with charge carriers can be regulated through the internal charge transfer or chemical doping. Here, we demonstrate the effect of a crystalline LaFeO3 buffer layer on amorphous and crystalline LaAlO3/SrTiO3 heterostructures with a different characteristic length of interlayer charge transfer. The LaFeO3 buffer layer acts as an energetically favored electron acceptor in both LaAlO3/SrTiO3 systems, resulting in modulation of interfacial carrier density and hence metal-to-insulator transition. Such different critical LaFeO3 thicknesses are explained in terms of distinct characteristic lengths of the redox-reaction-mediated and polar-catastrophe-dominated charge transfer, controlled by the interfacial atomic contact and Thomas-Fermi screening effect, respectively. Our results not only shed light on the complex interlayer charge transfer across oxide heterostructures but also establish a new route to precisely tailor the charge-transfer process at a functional interface by atomically engineered buffer layers. |
Tuesday, March 3, 2020 1:03PM - 1:15PM |
G64.00008: Synthesis and characterization of freestanding Sr2IrO4 epitaxial thin films Sujan Shrestha, Maryam Souri, Matthew Coile, Jiwoong Kim, John G Connell, Jong Woo Kim, Ambrose Seo Mott insulating states in Sr2IrO4 have attracted substantial interest due to the coexistence of strong spin-orbit interactions and electron correlation. To understand the effect of strain on Sr2IrO4, we have synthesized freestanding Sr2IrO4 epitaxial thin films. We have deposited Sr2IrO4 thin films on water-soluble Sr3Al2O6 buffer layers1 using pulsed laser deposition. XRD and RSM show that the Sr3Al2O6 buffer layer is strained compressively and Sr2IrO4 thin films follow the in-plane lattice constants of the buffer layer. However, the width of rocking curve of freestanding Sr2IrO4 thin films is about three times greater than as-grown Sr2IrO4 thin films. Also, the in-plane lattice constants of freestanding Sr2IrO4 thin films are slightly larger than Sr2IrO4 single crystals, presumably due to the introduction of defects during delamination. The optical spectra of freestanding Sr2IrO4 thin films show the blue shift of Jeff = ½ interband optical transitions compared to Sr2IrO4 thin films grown on SrTiO3. The blueshift is consistent with the result of tensile strained Sr2IrO4 thin films. Freestanding Sr2IrO4 thin films offer an opportunity to study their properties under large strain by combining with piezoelectric or mechanical devices. |
Tuesday, March 3, 2020 1:15PM - 1:27PM |
G64.00009: Epitaxial Growth of Perovskite Vanadates Jason Hoffman, Jennifer E. Hoffman Perovskite vanadates have recently attracted significant attention for their wide-range of functional properties. Below around 140 K, LaVO3 undergoes a structural transition, and becomes an orbitally ordered antiferromagnetic insulator. SrVO3, on the other hand, is a strongly correlated paramagnetic metal. In this work, we use oxygen-plasma assisted molecular beam epitaxy (MBE) to deposit epitaxial LaVO3 and SrVO3 thin films on insulating SrTiO3 substrates. We use ex-situ x-ray diffraction and magnetotransport measurements to compare the properties of (001) and (111)-oriented samples. We also discuss the behavior of LaVO3 / SrVO3 heterostructures, where above-room-temperature ferromagnetism has been reported and ferroelectricity has been predicted. |
Tuesday, March 3, 2020 1:27PM - 1:39PM |
G64.00010: Metal-Insulator Transition in Strongly Correlated Quantum Confined SrVO3 Superlattices Alyn James, Markus Aichhorn, Jude Laverock Superlattices (such as SrVO3/SrTiO3) have many interesting physical phenomena influenced by orbital degeneracy, quantum confinement, interfaces and electron-electron correlations to name a few. The use of varying the number of SrVO3 layers in superlattices gives a way to tune the strongly localized electron-electron correlations and the metal-insulator transition (MIT). These local correlations are beyond the predictive capabilities of standard density functional theory (DFT) calculations. Therefore, dynamical mean field theory (DMFT) needs to be used in conjunction with DFT (the DFT+DMFT method) to model these local correlations. |
Tuesday, March 3, 2020 1:39PM - 1:51PM |
G64.00011: Variable-temperature infrared microscopy of conducting oxide interfaces Stefano Gariglio, Weiwei Luo, Margherita Boselli, Jean-Marie Poumirol, Ivan Ardizzone, Jeremie Teyssier, Dirk Van Der Marel, Jean-Marc Triscone, Alexey B Kuzmenko Probing the local transport properties of two-dimensional electron systems confined at buried interfaces requires a non-invasive technique with a high spatial resolution. Using a scattering-type scanning near field optical microscopy, we study the conducting LaAlO3/SrTiO3 interface from room temperature down to 6 K [1]. We observe that the near-field optical signal is highly sensitive to the transport properties of the electron system. According to our model, such sensitivity originates from the interaction of the AFM tip with coupled plasmon–phonon modes. |
Tuesday, March 3, 2020 1:51PM - 2:03PM |
G64.00012: Direct imaging of the internal Bloch-components of polar-skyrmions and anti-hedgehogs in oxide heterostructures Yu-Tsun Shao, Sujit Das, Ruijuan Xu, Swathi Chandrika, Harold Hwang, Ramamoorthy Ramesh, David Anthony Muller Emergent topological textures in ferroelectric heterostructures such as polar vortices and skyrmions has been the playground for exploring new phases and phenomena, exhibiting exotic functionalities including emergent chirality and local negative capacitance. These topologies can be realized in superlattices of (PbTiO3)n/(SrTiO3)n, either on a rigid substrate or fully lifted-off as 2D-like membranes. The electric analog of magnetic skyrmions, nm-scale polar-skyrmion bubbles, was recently observed yet their local dipole configurations and response to external stimuli are less explored. Results of electron diffraction-imaging show that the in-plane polarization curling direction is preserved (counter-clockwise, CCW) whether the skyrmion bubbles are elongated, merged, or broken apart under the perturbation of a focused electron probe. Furthermore, an ordered skyrmion square lattice appeared when heated to 373 K, in which a CCW curling dipole moment was surrounded by arrays of anti-hedgehogs and clockwise curling dipole moments. |
Tuesday, March 3, 2020 2:03PM - 2:15PM |
G64.00013: Self-doping in Sr2VO4/Sr2IrO4 superlattice Yuhao Gu, Jiangping Hu, Hanghui Chen Searching for high transition temperature superconductivity in non-cuprate materials has always been one of the focus topics in condensed matter physics. Theoretically, Sr2IrO4 has been proposed as a promising candidate to induce high Tc superconductivity because of the similarity of its electronic structure to that of cuprates [1]. Experimentally, surface-electron doped Sr2IrO4 exhibits spectroscopic signatures that are consistent with a superconducting gap but a zero-resistance state is yet to be found [2,3]. Here we artificially design a Sr2VO4/Sr2IrO4 superlattice, composed of VO2 layer and IrO2 layer alternating along the c-axis. Our ab initio calculations show that only V-dxy band and Ir-J=1/2 band cross the fermi level, forming a coupled two-dimensional Hubbard model with self-doping. The superlattice can be used as an effective way to electron dope iridates without introducing chemical disorder. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700