Atomically flat (110) SrTiO3 and heteroepitaxy

Mukunoki, Yasushige; Nakagawa, N.; Susaki, Tomofumi; Hwang, Harold Y.

doi:10.1063/1.1920415

Cited by 54 publications

(33 citation statements)

References 21 publications

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“…This is in contrast to other reports 6,17 , where substrates treated at deposition conditions did not show any conductivity. However, similar low sheet resistance (5x10 -3  Ω/□) was recently reported in SrTiO 3 annealed at a low oxygen pressure of 5x10 -5 torr at 1000ºC 21 , which agrees with our data. They suggest that if the pressure is low enough, like 10 -6 mbar as for typical high-mobility LaAlO 3 /SrTiO 3 heterostructure depositions, even 800ºC is sufficient to reduce the SrTiO 3 .…”

supporting

confidence: 93%

Effect of oxygen vacancies in theSrTiO3substrate on the electrical properties of theLaAlO3∕SrTiO3interface

et al. 2007

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supporting

confidence: 93%

Effect of oxygen vacancies in theSrTiO3substrate on the electrical properties of theLaAlO3∕SrTiO3interface

et al. 2007

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“…On the other hand, for the case of LaAlO 3 /SrTiO 3 interfaces prepared on SrTiO 3 (110) substrate (Fig. 1c), both the SrTiO 3 and LaAlO 3 can be represented by planar stacks of (ABO) +4 and (O 2 ) −4 layers as proposed in Hwang et al 12 and Mukunoki et al 13 which leads to no polarization discontinuity at the interface. Consequently, no conductivity would be expected for such LaAlO 3 /SrTiO 3 (110) interfaces.…”

mentioning

confidence: 72%

Anisotropic two-dimensional electron gas at the LaAlO3/SrTiO3 (110) interface

et al. 2013

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The observation of a high-mobility two-dimensional electron gas between two insulating complex oxides, especially LaAlO3/SrTiO3, has enhanced the potential of oxides for electronics. The occurrence of this conductivity is believed to be driven by polarization discontinuity, leading to an electronic reconstruction. In this scenario, the crystal orientation has an important role and no conductivity would be expected, for example, for the interface between LaAlO3 and (110)-oriented SrTiO3, which should not have a polarization discontinuity. Here we report the observation of unexpected conductivity at the LaAlO3/SrTiO3 interface prepared on (110)-oriented SrTiO3, with a LaAlO3-layer thickness-dependent metal-insulator transition. Density functional theory calculation reveals that electronic reconstruction, and thus conductivity, is still possible at this (110) interface by considering the energetically favourable (110) interface structure, that is, buckled TiO2/LaO, in which the polarization discontinuity is still present. The conductivity was further found to be strongly anisotropic along the different crystallographic directions with potential for anisotropic superconductivity and magnetism, leading to possible new physics and applications.

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“…We emphasize that the substrates were treated under oxygen-rich atmosphere. Mukunoki et al 21 recently reported that a strongly reducing atmosphere was required to obtain flat STO ͑110͒ surfaces when using substrates with a smaller miscut angle ͑ϳ0.1°͒ and wider ͑ϳ200 nm͒ terraces. The XRR data measured from a LCMO͑110͒ film are plotted in Fig.…”

Section: Resultsmentioning

confidence: 99%

Structural and functional characterization of (110)-oriented epitaxial La2∕3Ca1∕3MnO3 electrodes and SrTiO3 tunnel barriers

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Sánchez

Fontcuberta

et al. 2007

Journal of Applied Physics

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La 2/3 Ca 1/3 MnO 3 ͑LCMO͒ films have been deposited on ͑110͒-oriented SrTiO 3 ͑STO͒ substrates. X-ray diffraction and high-resolution electron microscopy reveal that the ͑110͒ LCMO films are epitaxial and anisotropically in-plane strained, with higher relaxation along the ͓1-10͔ direction than along the ͓001͔ direction; x-ray absorption spectroscopy data signaled the existence of a single intermediate Mn 3+/4+ 3d-state at the film surface. Their magnetic properties are compared to those of ͑001͒ LCMO films grown simultaneously on ͑001͒ STO substrates It is found that ͑110͒ LCMO films present a higher Curie temperature ͑T C ͒ and a weaker decay of magnetization when approaching T C than their ͑001͒ LCMO counterparts. These improved films have been subsequently covered by nanometric STO layers. Conducting atomic-force experiments have shown that STO layers, as thin as 0.8 nm, grown on top of the ͑110͒ LCMO electrode, display good insulating properties. We will show that the electric conductance across ͑110͒ STO layers, exponentially depending on the barrier thickness, is tunnel-like. The barrier height in STO ͑110͒ is found to be similar to that of STO ͑001͒. These results show that the ͑110͒ LCMO electrodes can be better electrodes than ͑001͒ LCMO for magnetic tunnel junctions, and that ͑110͒ STO are suitable insulating barriers.

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Atomically flat (110) SrTiO3 and heteroepitaxy

Cited by 54 publications

References 21 publications

Effect of oxygen vacancies in theSrTiO3substrate on the electrical properties of theLaAlO3∕SrTiO3interface

Effect of oxygen vacancies in theSrTiO3substrate on the electrical properties of theLaAlO3∕SrTiO3interface

Anisotropic two-dimensional electron gas at the LaAlO3/SrTiO3 (110) interface

Structural and functional characterization of (110)-oriented epitaxial La2∕3Ca1∕3MnO3 electrodes and SrTiO3 tunnel barriers

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