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King PDC, Wei HI, Nie YF, Uchida M, Adamo C, Zhu S, He X, Božović I, Schlom DG, Shen KM. Atomic-scale control of competing electronic phases in ultrathin LaNiO₃. NATURE NANOTECHNOLOGY 2014; 9:443-7. [PMID: 24705511 DOI: 10.1038/nnano.2014.59] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/21/2014] [Indexed: 05/27/2023]
Abstract
In an effort to scale down electronic devices to atomic dimensions, the use of transition-metal oxides may provide advantages over conventional semiconductors. Their high carrier densities and short electronic length scales are desirable for miniaturization, while strong interactions that mediate exotic phase diagrams open new avenues for engineering emergent properties. Nevertheless, understanding how their correlated electronic states can be manipulated at the nanoscale remains challenging. Here, we use angle-resolved photoemission spectroscopy to uncover an abrupt destruction of Fermi liquid-like quasiparticles in the correlated metal LaNiO₃ when confined to a critical film thickness of two unit cells. This is accompanied by the onset of an insulating phase as measured by electrical transport. We show how this is driven by an instability to an incipient order of the underlying quantum many-body system, demonstrating the power of artificial confinement to harness control over competing phases in complex oxides with atomic-scale precision.
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Affiliation(s)
- P D C King
- 1] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA [2] Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - H I Wei
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - Y F Nie
- 1] Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA [2] Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - M Uchida
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - C Adamo
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - S Zhu
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - X He
- Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - I Božović
- Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - D G Schlom
- 1] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA [2] Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - K M Shen
- 1] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA [2] Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
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Snijders PC, Gao M, Guo H, Cao G, Siemons W, Gao H, Ward TZ, Shen J, Gai Z. A persistent metal-insulator transition at the surface of an oxygen-deficient, epitaxial manganite film. NANOSCALE 2013; 5:9659-9665. [PMID: 23979041 DOI: 10.1039/c3nr02343e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The oxygen stoichiometry has a large influence on the physical and chemical properties of complex oxides. Most of the functionality in e.g. catalysis and electrochemistry depends in particular on control of the oxygen stoichiometry. In order to understand the fundamental properties of intrinsic surfaces of oxygen-deficient complex oxides, we report on in situ temperature dependent scanning tunnelling spectroscopy experiments on pristine oxygen deficient, epitaxial manganite films. Although these films are insulating in subsequent ex situ in-plane electronic transport experiments at all temperatures, in situ scanning tunnelling spectroscopic data reveal that the surface of these films exhibits a metal-insulator transition (MIT) at 120 K, coincident with the onset of ferromagnetic ordering of small clusters in the bulk of the oxygen-deficient film. The surprising proximity of the surface MIT transition temperature of nonstoichiometric films with that of the fully oxygenated bulk suggests that the electronic properties in the surface region are not significantly affected by oxygen deficiency in the bulk. This carries important implications for the understanding and functional design of complex oxides and their interfaces with specific electronic properties in catalysis, oxide electronics and electrochemistry.
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Affiliation(s)
- Paul C Snijders
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Monkman EJ, Adamo C, Mundy JA, Shai DE, Harter JW, Shen D, Burganov B, Muller DA, Schlom DG, Shen KM. Quantum many-body interactions in digital oxide superlattices. NATURE MATERIALS 2012; 11:855-859. [PMID: 22902897 DOI: 10.1038/nmat3405] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/19/2012] [Indexed: 06/01/2023]
Abstract
Controlling the electronic properties of interfaces has enormous scientific and technological implications and has been recently extended from semiconductors to complex oxides that host emergent ground states not present in the parent materials. These oxide interfaces present a fundamentally new opportunity where, instead of conventional bandgap engineering, the electronic and magnetic properties can be optimized by engineering quantum many-body interactions. We use an integrated oxide molecular-beam epitaxy and angle-resolved photoemission spectroscopy system to synthesize and investigate the electronic structure of superlattices of the Mott insulator LaMnO(3) and the band insulator SrMnO(3). By digitally varying the separation between interfaces in (LaMnO(3))(2n)/(SrMnO(3))(n) superlattices with atomic-layer precision, we demonstrate that quantum many-body interactions are enhanced, driving the electronic states from a ferromagnetic polaronic metal to a pseudogapped insulating ground state. This work demonstrates how many-body interactions can be engineered at correlated oxide interfaces, an important prerequisite to exploiting such effects in novel electronics.
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Affiliation(s)
- Eric J Monkman
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
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Trinckauf J, Hänke T, Zabolotnyy V, Ritschel T, Apostu MO, Suryanarayanan R, Revcolevschi A, Koepernik K, Kim TK, Zimmermann MV, Borisenko SV, Knupfer M, Büchner B, Geck J. Electronic confinement and ordering instabilities in colossal magnetoresistive bilayer manganites. PHYSICAL REVIEW LETTERS 2012; 108:016403. [PMID: 22304275 DOI: 10.1103/physrevlett.108.016403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Revised: 09/16/2011] [Indexed: 05/31/2023]
Abstract
We present angle-resolved photoemission studies of (La{1-z}Pr{z}){2-2x}Sr{1+2x}Mn{2}O{7} with x=0.4 and z=0.1, 0.2, and 0.4 along with density functional theory calculations and x-ray scattering data. Our results show that the bilayer splitting in the ferromagnetic metallic phase of these materials is small, if not completely absent. The charge carriers are therefore confined to a single MnO{2} layer, which in turn results in a strongly nested Fermi surface. In addition to this, the spectral function also displays clear signatures of an electronic ordering instability well below the Fermi level. The increase of the corresponding interaction strength with z and its magnitude of ∼400 meV make the coupling to a bare phonon highly unlikely. Instead we conclude that fluctuating order, involving electronic and lattice degrees of freedom, causes the observed renormalization of the spectral features.
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Affiliation(s)
- J Trinckauf
- Leibniz Institute for Solid State and Materials Research IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
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