Anomalous Transport in Sketched Nanostructures at the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>LaAlO</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>Interface

Cheng, Guanglei; Veazey, Joshua P.; Irvin, Patrick; Cen, Cheng; Bogorin, Daniela F.; Bi, Feng; Huang, Mengchen; Lu, Shicheng; Bark, Chung Wung; Ryu, Sangwoo; Cho, Kwang-Hwan; Eom, Chang‐Beom; Levy, Jeremy

doi:10.1103/physrevx.3.011021

Cited by 33 publications

(28 citation statements)

References 34 publications

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“…Our calculations -both large-N and DMRG -show that our model gives rise to a helical wire. Remarkably, recent transport measurements can be interpreted as evidence that 1D channels at the LAO/STO interface are helical wires 50 .…”

Section: Discussionmentioning

confidence: 99%

Magnetic and superconducting ordering in one-dimensional nanostructures at the LaAlO3/SrTiO3interface

et al. 2013

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We formulate a model for magnetic and superconducting ordering in one-dimensional nanostructures at LaAlO3/SrTiO3 interfaces containing both localized magnetic moments and itinerant electrons. Though these both originate in Ti 3d orbitals, the former may be due to electrons more tightly-bound to the interface while the latter are extended over several layers. Only the latter contribute significantly to metallic conduction and superconductivity. In our model, the interplay between the two types of electrons, which is argued to be ferromagnetic, combined with strong spin-orbit coupling of the itinerant electrons, leads to magnetic ordering. Furthermore, we propose a model for interfacial superconductivity, consisting of random superconducting grains in the bulk STO driven, via coupling to the interface conduction band, towards long-ranged or quasi-long-ranged order. Most interestingly, the magnetic order and strong spin orbit coupling can lead in this manner to unconventional interfacial superconductivity, yielding a possible realization of Majorana physics.

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Section: Discussionmentioning

confidence: 99%

Magnetic and superconducting ordering in one-dimensional nanostructures at the LaAlO3/SrTiO3interface

et al. 2013

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“…This is most clear from the experiments by Cen et al [14][15][16][17][18] in which it was shown that regions of 2DEG at the buried interface can be induced by modifying the surface adsorbates with an appropriately biased atomic force microscopy (AFM) tip.…”

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confidence: 91%

Effects of structural relaxation, interdiffusion, and surface termination on two-dimensional electron gas formation at theLaAlO3/SrTiO3(001) interface

2015

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First-principles (generalized gradient approximation) calculations are presented for symmetric LaAlO3/SrTiO3/LaAlO3 [001] orientation slab models with varying thickness (3, 4, 5 unitcells) of the LaAlO3 (LAO) layers. The buckling of the layers and their effect on the slope of the layer averaged electrostatic potential and layer projected densities of states are studied. We find the buckling of the LAO layers to increase from the interface toward the surface, while the buckling of the AlO2 layers decreases toward the surface. The critical layer thickness for obtaining electrons in the Ti-d band of the STO is determined to be 4 layers within this model. Beyond this point, the sloped potential is confined to the 4 layers of LAO nearest to the interface. The electrons in the Ti-d states extend throughout the 5.5 layer thick STO region of our calculation. The sheet charge density of electrons in the STO conduction band is determined and found to be of order 1 − 3 × 10 13 e/cm 2 , in fair agreement with experimental values and an order of magnitude smaller than required by the polar discontinuity model. We also find still a significant change in the sheet density between the 4-LAO layer and 5-LAO layer model. It results in only dxy-like states being occupied for the 4-LAO layer case but other t2g bands becoming occupied for the 5-LAO layer case. The effects of H adsorption on surface O and OH adsorption on the surface Al are investigated for a model with 1/8 coverage of H and 1/4 coverage of OH. The former leads to electron doping of the SrTiO3 (STO) layer while the latter leads to a p-type surface. When both together are present, they cancel each other. For high H-coverage, we find that only a certain fraction of the electrons donated by H can be accommodated at the interface while the remaining go to the surface and lead to a reversal of the slope of the potential in the LAO region. Addition of 25 % Ti on Al sites into the first layer of LAO, already leads to a cancellation of the field in the LAO layer. It does not lead to Ti 3+ embedded in the LAO site but rather the Ti donates its additional electron to the interface 2DEG confined to the STO TiO2 layers. A swap of Al with Ti in the layers closest to the interface does not produce a 2DEG because the Al in the TiO2 interface layer provides holes compensating the electron doping from the Ti. Interdiffusion of Sr and La between the layers nearest to the interface does not lead to a 2DEG. These species are just electron donors in their own materials respectively. In a swap compensating dipoles result from the different nuclear charges but the electronic states near the gap are not affected. Thus no 2DEG formation occurs. On the other hand a SrLa placed in the middle of the LAO layer is found to facilitate electron transfer from the surface to the interface and could lead to a 2DEG. However, the latter had only a small sheet density.

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“…Electron correlations are believed to play a crucial role in determining the physics of this system that has been defi ned as a "2D electron liquid," 22 where electrons interact and can no longer be viewed as free electrons without interactions, and includes in its phase diagram superconductivity, 23 magnetism 24 (also coexisting with superconductivity itself), 25 -28 a semiconducting/ insulating state, 29 -31 negative compressibility, 32 a high mobility metallic state exhibiting quantum transport, 33 -35 including nonlocal transport, 36 and so-called Rashba-induced spin-orbit coupling leading to additional splitting of the d -bands (details can be found in Reference 37 ).…”

Section: Phase Diagrams and Electron Correlationsmentioning

confidence: 99%

Functional oxide interfaces

2013

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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 artifi cial 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.

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Anomalous Transport in Sketched Nanostructures at theLaAlO3/SrTiO3Interface

Cited by 33 publications

References 34 publications

Magnetic and superconducting ordering in one-dimensional nanostructures at the LaAlO3/SrTiO3interface

Magnetic and superconducting ordering in one-dimensional nanostructures at the LaAlO3/SrTiO3interface

Effects of structural relaxation, interdiffusion, and surface termination on two-dimensional electron gas formation at theLaAlO3/SrTiO3(001) interface

Functional oxide interfaces

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