Polaronic States and Superconductivity in WO3-x

Salje, Ekhard K. H.

doi:10.3390/condmat5020032

Cited by 11 publications

(20 citation statements)

References 37 publications

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“…As can be seen from equations (A4) and (A8), the widths are mostly determined by the gradient parameter s of the order parameter Q which is an order of magnitude larger than the Landau terms (see Table III). This value lies well within the general range of ferroelastic domain wall widths, which are generally between 0.2 and 2 nm at low temperatures [71].…”

Section: A Landau-ginzburg Domain Wall Profilessupporting

confidence: 79%

“…A recent density functional study of self-trapped polarons in WO 3 succeeded in capturing a polaronic state, with substantial lattice distortions, in the simulations [94], although the polaron was at higher energy than the delocalized electron. The role of electron localization and its coupling to the lattice is clearly an important area for future study [71].…”

Section: B Discussion Of Bulk Superconductivity Resultsmentioning

confidence: 99%

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Theoretical investigation of twin boundaries in WO3 : Structure, properties, and implications for superconductivity

Mascello

Spaldin

Narayan

et al. 2020

Phys. Rev. Research

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We present a theoretical study of the structure and functionality of ferroelastic domain walls in tungsten trioxide, WO 3. WO 3 has a rich structural phase diagram, with the stability and properties of the various structural phases strongly affected both by temperature and by electron doping. The existence of superconductivity is of particular interest, with the underlying mechanism as of now not well understood. In addition, reports of enhanced superconductivity at structural domain walls are particularly intriguing. Focusing specifically on the orthorhombic β phase, we calculate the structure and properties of the domain walls both with and without electron doping. We use two theoretical approaches: Landau-Ginzburg theory, with free energies constructed from symmetry considerations and parameters extracted from our first-principles density functional calculations, and direct calculation using large-scale, GPU-enabled density functional theory. We find that the structure of the β-phase domain walls resembles that of the bulk tetragonal α 1 phase, and that the electronic charge tends to accumulate at the walls. Motivated by this finding, we perform ab initio computations of electronphonon coupling in the bulk α 1 structure and extract the superconducting critical temperatures, T c , within Bardeen-Cooper-Schrieffer theory. Our results provide insight into the experimentally observed unusual trend of decreasing T c with increasing electronic charge carrier concentration.

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Section: A Landau-ginzburg Domain Wall Profilessupporting

confidence: 79%

Section: B Discussion Of Bulk Superconductivity Resultsmentioning

confidence: 99%

Theoretical investigation of twin boundaries in WO3 : Structure, properties, and implications for superconductivity

Mascello

Spaldin

Narayan

et al. 2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…III). This value lies well within the general range of ferroelastic domain wall widths, which are generally between 0.2 and 2 nm at low temperatures 72 .…”

Section: Results Of Domain Walls Calculations a Landau-ginzburg Domai...supporting

confidence: 79%

“…A recent density functional study of self-trapped polarons in WO 3 succeeded in capturing a polaronic state, with substantial lattice distortions, in the simulations 98 , although the polaron was at higher energy than the delocalized electron. The role of electron localization and its coupling to the lattice is clearly an important area for future study 72 .…”

Section: B Discussion Of Bulk Superconductivity Resultsmentioning

confidence: 99%

Theoretical investigation of twin boundaries in WO$_3$: Structure, properties and implications for superconductivity

Mascello,

Spaldin,

Narayan

et al. 2020

Preprint

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We present a theoretical study of the structure and functionality of ferroelastic domain walls in tungsten trioxide, WO3. WO3 has a rich structural phase diagram, with the stability and properties of the various structural phases strongly affected both by temperature and by electron doping. The existence of superconductivity is of particular interest, with the underlying mechanism as of now not well understood. In addition, reports of enhanced superconductivity at structural domain walls are particularly intriguing. Focusing specifically on the orthorhombic β phase, we calculate the structure and properties of the domain walls both with and without electron doping. We use two theoretical approaches: Landau-Ginzburg theory, with free energies constructed from symmetry considerations and parameters extracted from our first-principles density functional calculations, and direct calculation using large-scale, GPU-enabled density functional theory. We find that the structure of the β-phase domain walls resembles that of the bulk tetragonal α1 phase, and that the electronic charge tends to accumulate at the walls. Motivated by this finding, we perform ab initio computations of electron-phonon coupling in the bulk α1 structure and extract the superconducting critical temperatures , Tc, within Bardeen-Cooper-Schrieffer theory. Our results provide insight into the experimentally observed unusual trend of decreasing Tc with increasing electronic charge carrier concentration.

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“…Due to the intrinsic oxygen vacancies and formation of CS planes, the electronic and optical properties of tungsten suboxides differ from m-WO 3 . Such properties may provide an advantage in applications such as water splitting [ 39 ], near-infrared shielding [ 40 ], in anode materials for high-performance Li-ion batteries [ 41 ], field-effect-transistors [ 42 ], photocatalysis [ 43 ], and in-domain boundary engineering [ 44 ]. As it was shown [ 35 ], sub-stoichiometric WO 3−x nanosheets can be used as physisorption-based NO 2 sensors.…”

Section: Discussionmentioning

confidence: 99%

Synthesis and Characterization of Tungsten Suboxide WnO3n−1 Nanotiles

et al. 2021

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WnO3n−1 nanotiles, with multiple stoichiometries within one nanotile, were synthesized via the chemical vapour transport method. They grow along the [010] crystallographic axis, with the thickness ranging from a few tens to a few hundreds of nm, with the lateral size up to several µm. Distinct surface corrugations, up to a few 10 nm deep appear during growth. The {102}r crystallographic shear planes indicate the WnO3n−1 stoichiometries. Within a single nanotile, six stoichiometries were detected, namely W16O47 (WO2.938), W15O44 (WO2.933), W14O41 (WO2.928), W13O38 (WO2.923), W12O35 (WO2.917), and W11O32 (WO2.909), with the last three never being reported before. The existence of oxygen vacancies within the crystallographic shear planes resulted in the observed non-zero density of states at the Fermi energy.

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Polaronic States and Superconductivity in WO3-x

Cited by 11 publications

References 37 publications

Theoretical investigation of twin boundaries in WO3 : Structure, properties, and implications for superconductivity

Theoretical investigation of twin boundaries in WO3 : Structure, properties, and implications for superconductivity

Theoretical investigation of twin boundaries in WO$_3$: Structure, properties and implications for superconductivity

Synthesis and Characterization of Tungsten Suboxide WnO3n−1 Nanotiles

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