The hysteretic insulator-to-metal transition of VO2 is studied in detail for pulsed laser deposition grown thin films on TiO2 substrates, under variation of temperature and applied bias currents. ...This system is of interest for novel electronics based on memristive concepts, in particular as the resistive transition in these films occurs close to room temperature. Multiple, stable resistance states can be set controllably in the temperature range of the hysteretic phase transition by tailored temperature sweeps or by Joule heating induced by current pulses.
The rapid advent of the piezoelectric microelectromechanical systems (PiezoMEMS) field has created a tremendous demand for low hysteretic piezoelectric thin films on Si. In this work, we present the ...integration of epitaxial Pb(Mg
0.33
Nb
0.67
)O
3
-PbTiO
3
(PMN-PT) thin films with Si to enable device fabrication using state of the art methods. With optimized buffer layers and electronic contacts, high-quality low hysteretic PMN-PT thin films are integrated with Si, which is a significant stride towards employing PMN-PT thin film for PiezoMEMS devices. It is found that the processing of the necessary SrTiO
3
buffer layer is crucial to achieve the growth of phase-pure perovskite PMN-PT layers on Si. Furthermore, we propose the engineering of the electronic contact for the PMN-PT-on-Si capacitors to obtain low hysteretic polarization and displacement responses.
Abstract
Two-dimensional freestanding thin films of single crystalline oxide perovskites are expected to have great potential in integration of new features to the current Si-based technology. Here, ...we showed the ability to create freestanding single crystalline (011)- and (111)-oriented SrRuO
3
thin films using Sr
3
Al
2
O
6
water-sacrificial layer. The epitaxial Sr
3
Al
2
O
6
(011) and Sr
3
Al
2
O
6
(111) layers were realized on SrTiO
3
(011) and SrTiO
3
(111), respectively. Subsequently, SrRuO
3
films were epitaxially grown on these sacrificial layers. The freestanding single crystalline SrRuO
3
(011)
pc
and SrRuO
3
(111)
pc
films were successfully transferred on Si substrates, demonstrating possibilities to transfer desirable oriented oxide perovskite films on Si and arbitrary substrates.
The conductance confined at the interface of complex oxide heterostructures provides new opportunities to explore nanoelectronic as well as nanoionic devices. Herein we show that metallic interfaces ...can be realized in SrTiO3-based heterostructures with various insulating overlayers of amorphous LaAlO3, SrTiO3, and yttria-stabilized zirconia films. On the other hand, samples of amorphous La7/8Sr1/8MnO3 films on SrTiO3 substrates remain insulating. The interfacial conductivity results from the formation of oxygen vacancies near the interface, suggesting that the redox reactions on the surface of SrTiO3 substrates play an important role.
Functional perovskite oxides are recognized for their stunningly rich physics and for their potential as next-generation electronic materials. Their properties include high T
c superconductivity, ...colossal magnetoresistance, record-high dielectric/ferroelectric/piezoelectric performances, multiferroic behavior, resistive switching behavior, giant thermoelectric and magnetocaloric effects, giant ionic conduction, and catalytic behavior. Due to their intrinsic chemical and crystal similarities, functional oxides can be stacked in multilayer heterostructures exhibiting an astonishing degree of epitaxial perfection. Such artificial systems not only allow one to combine in a single device the functionalities of their individual layers, but often reveal an even wider range of emergent novel properties that can be surprisingly different from those of the single building blocks. The goal of this issue of MRS Bulletin is to present the state of the art of oxide interfaces in inscience and technology. Here we provide an introduction to their properties, serving as a base for the following topical articles.
Abstract
In order to bring the diverse functionalities of transition metal oxides into modern electronics, it is imperative to integrate oxide films with controllable properties onto the silicon ...platform. Here, we present asymmetric LaMnO
3
/BaTiO
3
/SrTiO
3
superlattices fabricated on silicon with layer thickness control at the unit-cell level. By harnessing the coherent strain between the constituent layers, we overcome the biaxial thermal tension from silicon and stabilize
c
-axis oriented BaTiO
3
layers with substantially enhanced tetragonality, as revealed by atomically resolved scanning transmission electron microscopy. Optical second harmonic generation measurements signify a predominant out-of-plane polarized state with strongly enhanced net polarization in the tricolor superlattices, as compared to the BaTiO
3
single film and conventional BaTiO
3
/SrTiO
3
superlattice grown on silicon. Meanwhile, this coherent strain in turn suppresses the magnetism of LaMnO
3
as the thickness of BaTiO
3
increases. Our study raises the prospect of designing artificial oxide superlattices on silicon with tailored functionalities.
A large variety of transport properties have been observed at the interface between the insulating oxides SrTiO3 and LaAlO3 such as insulation, 2D interface metallicity, 3D bulk metallicity, magnetic ...scattering, and superconductivity. The relation between the structure and the properties of the SrTiO3/LaAlO3 interface can be explained in a meaningful way by taking into account the relative contribution of three structural aspects: oxygen vacancies, structural deformations (including cation disorder), and electronic interface reconstruction. The emerging phase diagram is much richer than for related bulk oxides due to the occurrence of interface electronic reconstruction. The observation of this interface phenomenon is a display of recent advances in thin film deposition and characterization techniques, and provides an extension to the range of exceptional electronic properties of complex oxides.
The interface between the insulating oxides SrTiO3 and LaAlO3 shows a variety of transport properties. The properties of the interface can be explained by three structural aspects: oxygen vacancies, structural deformations (including cation disorder), and electronic interface reconstruction. Irrespective of the origin of mobile charge at these heterointerfaces, once harnessed and controlled all could lead to heterostructures, where the properties are determined by strong correlation effects, and therefore full of surprises.
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