Massive band gap variation in layered oxides through cation ordering

Balachandran, Prasanna V.; Rondinelli, James M.

doi:10.1038/ncomms7191

Cited by 37 publications

(26 citation statements)

References 55 publications

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“…As shown in Table 2, the data with deviating Mn oct -O int -Mn tet angle and R value for ABO 2.67 points towards a symmetry induced rotation difference. Still, the longer Mn oct -O int bond length can reduce the coupling between octahedral and tetrahedral layers 1 , and thus enable different magnetic sublattices in these layers.…”

Section: Resultsmentioning

confidence: 99%

“…The ABO 3 perovskite structure is prone to changes in stoichiometry, and recently there has been considerable interest in layered perovskite-derived structures like the Ruddlesden-Popper, Aurivillius and Dion-Jacobsen families with cation ordering 1–3 . Layering enforces anisotropic properties in the materials by decoupling the octahedral building blocks, and enabling functional properties such as ferroelectricity 3 , ferromagnetism 4 , and superconductivity 5 , making them interesting for novel device applications such as tunable microwave filters and optoelectronic components 1, 6 .…”

Section: Introductionmentioning

confidence: 99%

“…Layering enforces anisotropic properties in the materials by decoupling the octahedral building blocks, and enabling functional properties such as ferroelectricity 3 , ferromagnetism 4 , and superconductivity 5 , making them interesting for novel device applications such as tunable microwave filters and optoelectronic components 1, 6 . Interfaces between, or superlattices of, perovskites has also been used to confine electrons into 2 dimensions resulting in a 2-dimensional electron gas, where the most studied system is the LaAlO 3 /SrTiO 3 (LAO/STO) interface 7–9 .…”

Section: Introductionmentioning

confidence: 99%

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Spatially Confined Spin Polarization and magnetic sublattice control in (La,Sr)MnO3−δ Thin Films by Oxygen Vacancy Ordering

Moreau

Selbach

Tybell

2017

Sci Rep

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Perovskite oxides are known for their strong structure property coupling and functional properties such as ferromagntism, ferroelectricity and high temperature superconductivity. While the effect of ordered cation vacancies on functional properties have been much studied, the possibility of tuning the functionality through anion vacancy ordering has received much less attention. Oxygen vacancies in ferromagnetic La0.7Sr0.3MnO3−δ thin films have recently been shown to accumulate close to interfaces and form a brownmillerite structure (ABO2.5). This structure has alternating oxygen octahedral and tetrahedral layers along the stacking direction, making it a basis for a family of ordered anion defect controlled materials. We use density functional theory to study how structure and properties depend on oxygen stoichiometry, relying on a block-by-block approach by including additional octahedral layers in-between each tetrahedral layer. It is found that the magnetic and electronic structures follow the layers enforced by the ordered oxygen vacancies. This results in spatially confined electronic conduction in the octahedral layers, and decoupling of the magnetic sub-lattices in the octahedral and tetrahedral layers. These results demonstrate that anion defect engineering is a promising tool to tune the properties of functional oxides, adding a new avenue for developing functional oxide device technology.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spatially Confined Spin Polarization and magnetic sublattice control in (La,Sr)MnO3−δ Thin Films by Oxygen Vacancy Ordering

Moreau

Selbach

Tybell

2017

Sci Rep

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“…22 A total of 8 A-cation sites may be occupied by an equal number of La and Sr to give 70 total variants (including redundant structures), which are reduced down to 13 unique variants by symmetry, including 3 structures studied in Ref. 20. Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Recently up to 2 eV changes in electronic band gaps were predicted in LaSrAlO 4 by changes in the A cation arrangement in the n = 1 Ruddlesden-Popper (RP) structure. 20 The A 2 BO 4 RP structure consists of alternating perovskite/rock salt components, (ABO 3 )/(AO), stacked along the [001] direction. This layered crystal habit affords stacking of [AO] and [BO 2 ] layers, which can be utilized to direct the internal electric fields by sequencing of the charged layers: [LaO] 1+ , [SrO] 0 , and [AlO 2 ] 1− .…”

Section: Introductionmentioning

confidence: 99%

Tunable band structures in digital oxides with layered crystal habits

Shin

Rondinelli

2017

Phys. Rev. B

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We use density functional calculations to show heterovalent cation-order sequences enable control over band gap variations up to several electron-volts and band gap closure in the bulk band insulator LaSrAlO4. The band gap control originates from the internal electric fields induced by the digital chemical order, which induces picoscale band bending; the electric-field magnitude is mainly governed by the inequivalent charged monoxide layers afforded by the layered crystal habit. Charge transfer and ionic relaxations across these layers play secondary roles. This understanding is used to construct and validate a descriptor that captures the layer-charge variation and to predict changes in the electronic gap in layered oxides exhibiting antisite defects and in other chemistries.

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Internal Electric Field on Steering Charge Migration: Modulations, Determinations and Energy‐Related Applications

Yue

Fan

Xiang

2021

Adv Funct Materials

110

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Energy‐related problems induced by ever‐continuous fossil consumption have arisen as one of the most challenging issues in the 21st century, imposing urgent demands on advanced materials to achieve high energy utilization and a sustainable society. In various solar energy utilization and solar‐to‐fuel energy conversion processes, charge carriers are the main and inevitable participators, and the charge dynamics related to their generation, migration, separation, and utilization is the key to advance the material design for settling the above issues. Internal electric field (IEF), also named as built‐in electric field, could guide directional migration of charge carriers, achieving effective charge separation, utilization, and prolonged lifetimes. This critical review begins with the discussion on various modulation strategies toward the IEF together with in‐detail elucidated mechanisms on its formation. Some cascade systems for telling the conclusive role from the induced IEF and the intrinsic design strategy are discussed. Then, a summary of the state‐of‐the‐art advances in the characterization means toward the IEF from both quantitative and qualitative perspectives is provided. Finally presented are IEF modulations in several specific energy‐related applications concerning solar cell, photocatalysis, photodetectors, and batteries to better understand its superiority for well‐performed material design, followed by perspectives on future development and opportunities of the IEF design.

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Massive band gap variation in layered oxides through cation ordering

Cited by 37 publications

References 55 publications

Spatially Confined Spin Polarization and magnetic sublattice control in (La,Sr)MnO3−δ Thin Films by Oxygen Vacancy Ordering

Spatially Confined Spin Polarization and magnetic sublattice control in (La,Sr)MnO3−δ Thin Films by Oxygen Vacancy Ordering

Tunable band structures in digital oxides with layered crystal habits

Internal Electric Field on Steering Charge Migration: Modulations, Determinations and Energy‐Related Applications

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