Controlled lateral anisotropy in correlated manganite heterostructures by interface-engineered oxygen octahedral coupling

Liao, Zhaoliang; Huijben, Mark; Zhong, Zhicheng; Gauquelin, Nicolas; Macke, S.; Green, R. J.; Aert, Sandra Van; Verbeeck, Johan; Tendeloo, Gustaaf Van; Held, Karsten; Sawatzky, G. A.; Koster, Gertjan; Rijnders, Guus

doi:10.1038/nmat4579

Cited by 333 publications

(326 citation statements)

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“…The electronic structure calculations of all LSMO slabs reveal small rotations of MnO 6 octahedrons (in order of 1°) along c direction, which coincide well with previous experimental 73 and theoretical 74 To define coordination types of pentacene molecule, 2-ZGNR and 4-ZGNR on SrOterminated surface, standard notations of coordination sites h 1 , h 2 , h 3 and h 6 are used throughout the text to denote the coordination of Sr surface ions to single carbon atom, the middle of C-C bond, C 3 triangle fragment and the center of C 6 hexagons, respectively. For 4-ZBNNR the same notations are used with h 2 and h 6 correspond to the middle of B-N bond and center of B 3 N 3 hexagon.…”

Section: Resultssupporting

confidence: 88%

Theoretical Investigation of the Interfaces and Mechanisms of Induced Spin Polarization of 1D Narrow Zigzag Graphene- and h-BN Nanoribbons on a SrO-Terminated LSMO(001) Surface

et al. 2017

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The structure of the interfaces and the mechanisms of induced spin polarization of 1D infinite and finite narrow graphene-and h-BN zigzag nanoribbons placed on SrO-terminated La 1-x Sr x MnO 3 (LSMO) (001) surface were studied using Density Functional (DFT) electronic structure calculations. It was found that the p-conjugated nanofragments are bounded with LSMO(001) surface by weak disperse interactions. The types of coordination of the fragments, the strength of bonding and the rate of spin polarization depend upon the nature of the fragments. Infinite and finite graphene narrow zigzag nanoribbons are characterized by the lift of the spin degeneracy and strong spin-polarization caused by interface-induced structural asymmetry and oxygen-mediated indirect exchange interactions with Mn ions of LSMO support. Spin polarization changes the semiconducting nature of infinite graphene nanoribbons to half-metallic state with visible spin-up density of states at the Fermi level. The h-BN nanoribbon binding energy is weaker than graphene nanoribbon ones with noticeably shorter interlayer distance. The asymmetry effect and indirect exchange interactions cause spin polarization of h-BN nanoribbon as well with formation of embedded states inside the band gap. The results show a possibility to use one-atom thick nanofragments to design LSMO-based heterostructures for spintronic nanodevices with h-BN as an inert spacer to develop different potential barriers.Keywords: LSMO thin film, pentacene, spin states, induced spin polarization, graphene and h-BN nanoribbons, heterostructures, DFT+U calculations.* Author to whom correspondence should be addressed.The progress in developing of graphene-based spintronic nanodevices is related with weak spin-orbital interactions of carbon atoms, which enable one to utilize extremely high mobility of electrons together with long spin transport length. [1][2][3] The effectiveness of spin injection in carbon nanostructures by ferromagnetic supports (e.g. Ni(111)) has already been discovered experimentally and interpreted theoretically. 4,5 In particular, high magnetoresistance has been detected in p-conjugated organic media on ferromagnetic supports. 6-10 Isolating h-BN fragments located between graphene and ferromagnetic metallic supports have been used for chemical passivation of the surfaces and creation of tunnel contacts to promote graphene spin injection. [11][12][13] It was demonstrated that in 2D nanoheterostructures the injection coherence length could achieve up to 350 µm 14,15 due to interface-related Buchkov-Rashba effect. 16,17,18 Bychkov-Rashba effect is caused by the lift of spin degeneracy due to structure inverse asymmetry (SIA) 18 in 2D electron gas (2DEG) at the interfaces. 2DEG is confined by the effective electric field oriented in [001] direction caused by SIA effect, which, in many cases, is much stronger than the bulk symmetrical features. 19 For nonmagnetic surfaces, the Rashba field lifts the spin degeneracy of the surface states, 19 whereas for magnetic ones, it le...

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Section: Resultssupporting

confidence: 88%

Theoretical Investigation of the Interfaces and Mechanisms of Induced Spin Polarization of 1D Narrow Zigzag Graphene- and h-BN Nanoribbons on a SrO-Terminated LSMO(001) Surface

et al. 2017

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“…For instance, in the case of the LaAlO 3 =SrTiO 3 system, the internal field may be manipulated by directly writing charges on the surface [41,42]. Similar approaches may be used to modulate magnetism [43] or ferroelectricity [44] in other systems, thus significantly expanding the scopes of material design at perovskite interfaces. We conclude, therefore, that this kind of complex interplay may be used as a general tool to engineer potentially useful physical properties in atomically thin ABO 3 -perovskite structures.…”

Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 8 Septemmentioning

confidence: 99%

Competition between Polar and Nonpolar Lattice Distortions in Oxide Quantum Wells: New Critical Thickness at Polar Interfaces

et al. 2017

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Two basic lattice distortions permeate the structural phase diagram of oxide perovskites: antiferrodistortive (AFD) rotations and tilts of the oxygen octahedral network and polar ferroelectric modes. With some notable exceptions, these two order parameters rarely coexist in a bulk crystal, and understanding their competition is a lively area of active research. Here we demonstrate, by using the LaAlO 3 =SrTiO 3 system as a test case, that quantum confinement can be a viable tool to shift the balance between AFD and polar modes and selectively stabilize one of the two phases. By combining scanning transmission electron microscopy (STEM) and first-principles-based models, we find a crossover between a bulklike LaAlO 3 structure where AFD rotations prevail, to a strongly polar state with no AFD tilts at a thickness of approximately three unit cells; therefore, in addition to the celebrated electronic reconstruction, our work unveils a second critical thickness, related not to the electronic properties but to the structural ones. We discuss the implications of these findings, both for the specifics of the LaAlO 3 =SrTiO 3 system and for the general quest towards nanoscale control of material properties. DOI: 10.1103/PhysRevLett.119.106102 Polar lattice distortions [1,2] and "antiferrodistortive" (AFD) tilts of the BO 6 octahedral network [3,4] are ubiquitous in the physics of ABO 3 perovskite oxides and largely responsible for their interesting functional properties. Indeed, the former potentially leads to ferroelectricity, while the latter often has a dramatic impact over the orbital and magnetic orders. Although some notable exceptions exist (e.g., BiFeO 3 ), the two order parameters tend to be mutually contraindicated in a bulk perovskite crystal [3]. Such a competition has often been used in the continuing search for new multiferroics or, more generally, to engineer exotic phases via atomic-scale design, as in the recent report of polar metals at perovskite interfaces [5]. Overall, controlling the balance between the competing polar and AFD phases offers exciting opportunities to realize novel properties "à la carte." Such a balance is often delicate, as both types of lattice distortions and their mutual couplings are governed by a subtle interplay of short-range covalency (related to B-O bonding) and long-range electrostatic (or elastic) effects [6].Atomic-scale confinement appears as an ideal tool to tune the competition between different order parameters, as it is known to profoundly alter the spectrum of lattice and electronic excitations of crystalline materials [7][8][9][10][11]. In ferroelectrics, for example, size effects play a dramatic role in determining the stability of the polar state [12,13]. The driving force that determines the critical thickness for ferroelectricity is of an electrostatic nature and manifests itself as a "depolarizing" electric field that is antiparallel to the film's polarization. Therefore, the question of whether nonferroelectric (and hence insensitive to macroscopic depol...

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“…25,26 This result was quite surprising considering bulk SrRhO 3 is an orthorhombic perovskite. So to test this, we performed XRD reciprocal space mapping for the all variants of the STO 103 reflection by azimuthally rotating the sample (see Fig.…”

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confidence: 99%

Electronic and magnetic properties of epitaxial SrRhO3 films

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Strong interplay of fundamental order parameters in complex oxides are known to give rise to exotic physical phenomena. The 4d transition metal oxide SrRhO 3 has generated much interest, but advances have been hindered by difficulties in preparing single crystalline phases. Here, we have epitaxially stabilized high quality single crystalline SrRhO 3 films and investigated their structural, electronic, and magnetic properties. We determine that their properties significantly differ from the paramagnetic metallic ground state that governs bulk samples and are strongly related to rotations of the RhO 6 octahedra.

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Controlled lateral anisotropy in correlated manganite heterostructures by interface-engineered oxygen octahedral coupling

Cited by 333 publications

References 49 publications

Theoretical Investigation of the Interfaces and Mechanisms of Induced Spin Polarization of 1D Narrow Zigzag Graphene- and h-BN Nanoribbons on a SrO-Terminated LSMO(001) Surface

Theoretical Investigation of the Interfaces and Mechanisms of Induced Spin Polarization of 1D Narrow Zigzag Graphene- and h-BN Nanoribbons on a SrO-Terminated LSMO(001) Surface

Competition between Polar and Nonpolar Lattice Distortions in Oxide Quantum Wells: New Critical Thickness at Polar Interfaces

Electronic and magnetic properties of epitaxial SrRhO3 films

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