Tolerance Factor and Cation–Anion Orbital Interactions Differentiating the Polar and Antiferrodistortive Structures of Perovskite Oxides <i>AB</i>O<sub>3</sub>

Whangbo, Myung‐Hwan; Gordon, Elijah E.; Bettis, Jerry L.; Bussmann‐Holder, A.; Köhler, Jürgen

doi:10.1002/zaac.201500058

Cited by 17 publications

(15 citation statements)

References 57 publications

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“…This finding is particularly attractive: because of the chemical bonding, the polar phase usually occurs in nonmagnetic perovskites (30,31,49,50). With recent development of new mechanisms for achieving coexisting ferroelectricity and ferromagnetism (51, 52), our results provide a useful path for how to achieve ferroelectric ferromagnets via interface-induced structural transition in the ultrathin limit (15,16,53,54).…”

Section: Significancementioning

confidence: 75%

“…Indeed, large electrostatic and electrochemical effects across the interface have been observed to modulate magnetism (25)(26)(27)(28)(29). However, structurally, the two materials belong to distinct phases: BTO exhibits a polar phase, where metal and oxygen ions displace against one another, whereas LSMO exhibits a nonpolar antiferrodistortive (AFD) phase, where oxygen octahedrons have tilts (30,31). One would expect that such structural conflict can be radically magnified when reducing the LSMO thickness into the ultrathin regime, where two adjacent BTO/ LSMO interfaces are geometrically close.…”

Section: Significancementioning

confidence: 99%

See 1 more Smart Citation

Interface-induced multiferroism by design in complex oxide superlattices

Guo

Wang

Dong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Interfaces between materials present unique opportunities for the discovery of intriguing quantum phenomena. Here, we explore the possibility that, in the case of superlattices, if one of the layers is made ultrathin, unexpected properties can be induced between the two bracketing interfaces. We pursue this objective by combining advanced growth and characterization techniques with theoretical calculations. Using prototype La 2/3 Sr 1/3 MnO 3 (LSMO)/ BaTiO 3 (BTO) superlattices, we observe a structural evolution in the LSMO layers as a function of thickness. Atomic-resolution EM and spectroscopy reveal an unusual polar structure phase in ultrathin LSMO at a critical thickness caused by interfacing with the adjacent BTO layers, which is confirmed by first principles calculations. Most important is the fact that this polar phase is accompanied by reemergent ferromagnetism, making this system a potential candidate for ultrathin ferroelectrics with ferromagnetic ordering. Monte Carlo simulations illustrate the important role of spin-lattice coupling in LSMO. These results open up a conceptually intriguing recipe for developing functional ultrathin materials via interface-induced spin-lattice coupling.spin-lattice coupling | interfaces | magnetic/electric | structural transition | ultrathin films I nterface physics has emerged as one of the most popular methods to discover unique phenomena caused by broken symmetry (1-6). In transition metal oxide (TMO) interfaces, the different electronic, magnetic, lattice, and orbital properties of two adjoined materials lead to fascinating properties that are often radically different from those of the two component bulk materials (7-10). It would seem that we are on the verge of being able to design (11) or engineer (12) the properties of interfaces.Although the behavior of individual interfaces has been widely investigated, how two or more interfaces behave within superlattices (SLs) remains an interesting and open topic (13,14). As shown in Fig. 1A, when two interfaces are geometrically close enough, they can drastically alter the properties of the material in between because of proximity effects. Unlike layered compounds, such as Fe-based superconductors and cuprates, which have pronounced 2D properties, most perovskites with the chemical formula ABO 3 exhibit drastic decreases in their functionalities under reduced dimensionality (i.e., ultrathin materials). This property has hindered the exploration and development of active low-dimensional materials (15, 16). Therefore, exploring ultrathin materials confined by two interfaces is a rational approach to see whether interfacial effects can be exploited to achieve desired functionalities.In this work, we present an example of using the structural phase change induced by two adjacent interfaces as a route to design ultrathin TMOs. We choose two materials with distinct properties: BaTiO 3 (BTO), which in its bulk form, is polar ferroelectric, and La 2/3 Sr 1/3 MnO 3 (LSMO), which in its bulk form, is nonpolar/tilt ferromagnetic....

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Section: Significancementioning

confidence: 75%

Section: Significancementioning

confidence: 99%

Interface-induced multiferroism by design in complex oxide superlattices

Guo

Wang

Dong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Interestingly, the largest decrease of mobility is seen near x = 0.5 and higher, possibly due to the increasing number of intermixing atoms that acting as "charged impurities" in transport, although significant structural defect is not shown in RHEED and XRD. The general trend of reduced mobility with increasing x may also be explained by the different ionic radii of Eu 2+ and La 3+ that induce structural distortions resulting in variation of the Ti-O-Ti bond angle, from near 180° in bulk ETO to 157° in bulk LTO [31,37,38]. This distortion leads to a reduction of the hopping integral, possibly decreasing mobility as a result.…”

Section: B Electrical Transport Measurementmentioning

confidence: 99%

Controlling the electrical and magnetic ground states by doping in the complete phase diagram of titanate Eu1−xLaxTiO3 thin films

Shin

Liu

et al. 2020

Phys. Rev. B

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EuTiO 3 , a band insulator, and LaTiO 3 , a Mott insulator, are both antiferromagnetic with transition temperatures ~ 5.5 K and ~ 160 K, respectively. Here, we report the synthesis of Eu 1x La x TiO 3 thin films with x = 0 to 1 by oxide molecular beam epitaxy. The films in the full range have high crystalline quality and show no phase segregation, allowing us carry out transport measurements to study their electrical and magnetic properties. From x = 0.03 to 0.95, Eu 1-x La x TiO 3 films show conduction by electrons as charge carriers, with differences in carrier densities and mobilities, contrary to the insulating nature of pure EuTiO 3 and LaTiO 3 . Following a rich phase diagram, the magnetic ground states of the films vary with increasing La-doping level, changing Eu 1-x La x TiO 3 from an antiferromagnetic insulator to an antiferromagnetic metal, a ferromagnetic metal, a paramagnetic metal, and back to an antiferromagnetic insulator. These emergent properties reflect the evolutions of the band structure, mainly at the Ti t 2g bands near the Fermi level, when Eu 2+ are gradually replaced by La 3+ . This work sheds light on this method for designing the electrical and magnetic properties in strongly-correlated oxides and completes the phase diagram of the titanate Eu 1-x La x TiO 3 .

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“…Generally, for each perovskite , the Goldschmidt tolerance factor ( √ [63], where , , and are the ionic radii of A-site cation, B-site cation, and oxygen, respectively) provides a reasonably accurate guideline in identifying whether FE displacement or AFD rotation is more likely to occur [64].…”

Section: Structural Properties and Transitionsmentioning

confidence: 99%

Physics of SrTiO₃-based heterostructures and nanostructures: a review

et al. 2018

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1 Overview 1 1.1 Introduction 1 1.1.1 Oxide growth techniques are rooted in search for high-Tc superconductors 2 1.1.2 First reports of interface conductivity 2 1.2 2D physics 2 1.3 Emergent properties of oxide heterostructures and nanostructures 3 1.4 Outline 3 2 Relevant properties of SrTiO3 3 2.1 Structural properties and transitions 3 2.2 Ferroelectricity, Paraelectricity and Quantum Paraelectricity 4 2.3 Electronic structure 5 2.4 Defects 6 2.4.1 Oxygen vacancies 6 2.4.2 Terraces 7 2.5 Superconductivity 7 3 SrTiO3-based heterostructures and nanostructures 8 3.1 Varieties of heterostructures 8 3.1.1 SrTiO3 only 9 3.1.2 LaAlO3/SrTiO3 9 3.1.3 Other heterostructures formed with SrTiO3 10 3.2 Thin-film growth 10 3.2.1 Substrates 10 3.2.2 SrTiO3 surface treatment 11 3.2.3 Pulsed Laser Deposition 11 3.2.4 Atomic Layer Deposition 13 3.2.5 Molecular Beam Epitaxy 14 3.2.6 Sputtering 15 3.3 Device Fabrication 15 3.3.1 "Conventional" photolithography - Thickness Modulation, hard masks, etc. 15 3.3.2 Ion beam irradiation 16 3.3.3 Conductive-AFM lithography 16 4 Properties and phase diagram of LaAlO3/SrTiO3 16 4.1 Insulating state 16 4.2 Conducting state 17 4.2.1 Confinement thickness (the depth profile of the 2DEG) 17 4.3 Metal-insulator transition and critical thickness 18 4.3.1 Polar catastrophe ( electronic reconstruction) 18 4.3.2 Oxygen Vacancies 19 4.3.3 Interdiffusion 20 4.3.4 Polar Interdiffusion + oxygen vacancies + antisite pairs 20 4.3.5 Role of surface adsorbates 21 4.3.6 Hidden FE like distortion - Strain induced instability 21 4.4 Structural properties and transitions 21 4.5 Electronic band structure 22 4.5.1 Theory 22 4.5.2 Experiment 23 4.5.3 Lifshitz transition 24 4.6 Defects, doping, and compensation 25 4.7 Magnetism 25 4.7.1 Experimental evidence 25 4.7.2 Two types of magnetism 27 4.7.3 Ferromagnetism 27 4.7.4 Metamagnetism 28 4.8 Superconductivity 28 4.9 Optical properties 29 4.9.1 Photoluminesce experiments 29 4.9.2 Second Harmonic Generation 29 4.10 Coexistence of superconductivity and magnetism 30 4.11 Magnetic and conducting phases 30 5 Quantum transport in LaAlO3/SrTiO3 heterostructures and microstructures 31 5.1 2D transport 31 5.2 Inhomogeneous Transport 31 5.3 Anisotropic Magnetoresistance 32 5.4 Spin-orbit coupling 32 5.5 Anomalous Hall Effect 34 5.6 Shubnikov-de Haas (SdH) Oscillation 35 5.7 Quantum Hall Effect 37 5.8 Spintronic Effects 38 6 Quantum transport in LaAlO3/SrTiO3 nanostructures 39 6.1 Quasi-1D Superconductivity 39 6.2 Universal conductance fluctuations 40 6.3 Dissipationless Electronic Waveguides 40 6.4 Superconducting Quantum Interference Devices (SQUID) 41 6.5 Electron pairing without superconductivity 41 6.6 Tun...

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Tolerance Factor and Cation–Anion Orbital Interactions Differentiating the Polar and Antiferrodistortive Structures of Perovskite Oxides ABO₃

Cited by 17 publications

References 57 publications

Interface-induced multiferroism by design in complex oxide superlattices

Interface-induced multiferroism by design in complex oxide superlattices

Controlling the electrical and magnetic ground states by doping in the complete phase diagram of titanate Eu1−xLaxTiO3 thin films

Physics of SrTiO₃-based heterostructures and nanostructures: a review

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Tolerance Factor and Cation–Anion Orbital Interactions Differentiating the Polar and Antiferrodistortive Structures of Perovskite Oxides ABO3

Cited by 17 publications

References 57 publications

Interface-induced multiferroism by design in complex oxide superlattices

Interface-induced multiferroism by design in complex oxide superlattices

Controlling the electrical and magnetic ground states by doping in the complete phase diagram of titanate Eu1−xLaxTiO3 thin films

Physics of SrTiO3-based heterostructures and nanostructures: a review

Contact Info

Product

Resources

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Tolerance Factor and Cation–Anion Orbital Interactions Differentiating the Polar and Antiferrodistortive Structures of Perovskite Oxides ABO₃

Physics of SrTiO₃-based heterostructures and nanostructures: a review