Length scales of interfacial coupling between metal and insulator phases in oxides

Domínguez, Claribel; Georgescu, Alexandru B.; Mundet, Bernat; Zhang, Yajun; Fowlie, Jennifer; Mercy, Alain; Waelchli, Adrien; Catalano, Sara; Alexander, Duncan T. L.; Ghosez, Philippe; Georges, Antoine; Millis, Andrew J.; Gibert, Marta; Triscone, Jean‐Marc

doi:10.1038/s41563-020-0757-x

Cited by 57 publications

(68 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1g ). Similar coupling regions observed in other perovskite heterostructures result in extraordinary electrical and magnetic properties 3 , 7 – 9 , 19 – 22 . We define the structurally diffuse interface width as one unit cell centred at the chemically abrupt TiO 2 interface as schematically shown in Fig.…”

Section: Mainsupporting

confidence: 71%

“…The hierarchy of lattices in superlattices presents a tunable phonon–material interaction where, at small-to-moderate-period thicknesses, coherent and localized interface phonons have a major role in controlling properties. The vibrations and coupling present at interfaces in superlattices, in a broader context, occur at other interphase and intergranular boundaries and can result in remarkable properties 3 , 14 – 24 . Probing vibrations with the lateral spatial resolution required to provide knowledge that can be used for interface engineering and customization of thermal and infrared properties has remained prohibitively difficult 10 , 12 , 15 , 25 – 27 .…”

Section: Mainmentioning

confidence: 99%

“…3, Supplementary Tables 1, 2 ). Thus, as the layer thickness decreases, the underlying crystal structure adapts, which could be enabled by octahedral tilt 3 , 4 , 19 , 21 , 22 .…”

Section: Mainmentioning

confidence: 99%

See 2 more Smart Citations

Emergent interface vibrational structure of oxide superlattices

Hoglund

Bao

O’Hara

et al. 2022

Nature

View full text Add to dashboard Cite

As the length scales of materials decrease, the heterogeneities associated with interfaces become almost as important as the surrounding materials. This has led to extensive studies of emergent electronic and magnetic interface properties in superlattices1–9. However, the interfacial vibrations that affect the phonon-mediated properties, such as thermal conductivity10,11, are measured using macroscopic techniques that lack spatial resolution. Although it is accepted that intrinsic phonons change near boundaries12,13, the physical mechanisms and length scales through which interfacial effects influence materials remain unclear. Here we demonstrate the localized vibrational response of interfaces in strontium titanate–calcium titanate superlattices by combining advanced scanning transmission electron microscopy imaging and spectroscopy, density functional theory calculations and ultrafast optical spectroscopy. Structurally diffuse interfaces that bridge the bounding materials are observed and this local structure creates phonon modes that determine the global response of the superlattice once the spacing of the interfaces approaches the phonon spatial extent. Our results provide direct visualization of the progression of the local atomic structure and interface vibrations as they come to determine the vibrational response of an entire superlattice. Direct observation of such local atomic and vibrational phenomena demonstrates that their spatial extent needs to be quantified to understand macroscopic behaviour. Tailoring interfaces, and knowing their local vibrational response, provides a means of pursuing designer solids with emergent infrared and thermal responses.

show abstract

Section: Mainsupporting

confidence: 71%

Section: Mainmentioning

confidence: 99%

See 1 more Smart Citation

Emergent interface vibrational structure of oxide superlattices

Hoglund

Bao

O’Hara

et al. 2022

Nature

View full text Add to dashboard Cite

show abstract

“…This method has recently enabled the spatial mapping of the electronic phases in rare-earth nickelate superlattices to almost atomic resolution, revealing how structural and electronic properties are coupled at the interfaces of these novel, artificially engineered materials [41]. Understanding the coupling length scales has been crucial for harnessing the phase transition in such devices [42]. However, the use of PCA is less convenient to effectively unmix overlapped spectral features since the resulting orthogonal components do not have a physical meaning.…”

Section: Atomic Scale Probes Of Condensed Matter Systemsmentioning

confidence: 99%

Machines for Materials and Materials for Machines: Metal-Insulator Transitions and Artificial Intelligence

et al. 2021

Self Cite

View full text Add to dashboard Cite

In this perspective, we discuss the current and future impact of artificial intelligence and machine learning for the purposes of better understanding phase transitions, particularly in correlated electron materials. We take as a model system the rare-earth nickelates, famous for their thermally-driven metal-insulator transition, and describe various complementary approaches in which machine learning can contribute to the scientific process. In particular, we focus on electron microscopy as a bottom-up approach and metascale statistical analyses of classes of metal-insulator transition materials as a bottom-down approach. Finally, we outline how this improved understanding will lead to better control of phase transitions and present as an example the implementation of rare-earth nickelates in resistive switching devices. These devices could see a future as part of a neuromorphic computing architecture, providing a more efficient platform for neural network analyses – a key area of machine learning.

show abstract

“…The present study demonstrates that the MIT can be controlled by the RT effect in double QW structures of strongly correlated oxides. Our observations offer valuable insight into the quest for novel quantum phenomena using oxide heterostructures [6][7][8][9][10][30][31][32][33] , since the U/W ratio can be controlled by designing the wavefunction of their strongly correlated electrons. In addition, from an applied perspective, the MIT control based on the double QW structure studied here has fundamental advantages over conventional FET control 4,5,9 : the Mott transition may be operated by aligning two quantization levels through the application of a small voltage, and the entire QW will undergo a MIT irrespective of the limitation imposed by Thomas-Fermi screening.…”

mentioning

confidence: 94%

Resonant tunneling driven metal-insulator transition in double quantum-well structures of strongly correlated oxide

Yukawa

Kobayashi

Shiga

et al. 2021

Preprint

View full text Add to dashboard Cite

The metal-insulator transition (MIT), a fascinating phenomenon occurring in some strongly correlated materials, is of central interest in modern condensed-matter physics. Controlling the MIT by external stimuli is a key technological goal for applications in future electronic devices. However, the standard control by means of the field effect, which works extremely well for semiconductor transistors, faces severe difficulties when applied to the MIT. Hence, a radically different approach is needed. Here, we report an MIT induced by resonant tunneling (RT) in double quantum well (QW) structures of strongly correlated oxides. In our structures, two layers of the strongly correlated conductive oxide SrVO3 (SVO) sandwich a barrier layer of the band insulator SrTiO3 (STO). The top QW is a marginal Mott-insulating SVO layer, while the bottom QW is a metallic SVO layer. Angle-resolved photoemission spectroscopy experiments reveal that the top QW layer becomes metallized when the thickness of the tunneling barrier layer is reduced. An analysis based on band structure calculations indicates that RT between the quantized states of the double QW induces the MIT. Our work opens avenues for realizing the Mott-transistor based on the wave-function engineering of strongly correlated electrons.

show abstract

Length scales of interfacial coupling between metal and insulator phases in oxides

Cited by 57 publications

References 48 publications

Emergent interface vibrational structure of oxide superlattices

Emergent interface vibrational structure of oxide superlattices

Machines for Materials and Materials for Machines: Metal-Insulator Transitions and Artificial Intelligence

Resonant tunneling driven metal-insulator transition in double quantum-well structures of strongly correlated oxide

Contact Info

Product

Resources

About