Superconductivity in Mo-Re and Nb-Ir<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>σ</mml:mi></mml:math>Phases

Koch, Carl C.; Scarbrough, J. O.

doi:10.1103/physrevb.3.742

Cited by 29 publications

(11 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…24 In this work, the isostructural Nb 5 Ir 3 attracts our attention in consideration of the superconducting nature of the Nb element and sporadic reports on the superconducting behavior of the binary Nb-Ir phases. [25][26][27] In virtue of the experiments and theoretical calculations, we find that the phase diagram for Nb-Ir hosts a hexagonal phase with interesting interplay of superconductivity and electride state. The characteristic band structure can be engineered via introduction of guest atoms into the cavity sites for targeted properties, showing a rather intriguing base for the development of intrinsic, stable and functional electrides.…”

Section: Introductionmentioning

confidence: 79%

See 1 more Smart Citation

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

et al. 2017

View full text Add to dashboard Cite

Electrides are unique in the sense that they contain localized anionic electrons in the interstitial regions. Yet they exist with a diversity of chemical compositions, especially under extreme conditions, implying generalized underlying principles for their existence. What is rarely observed is the combination of electride state and superconductivity within the same material, but such behavior would open up a new category of superconductors. Here, we report a hexagonal Nb 5 Ir 3 phase of Mn 5 Si 3 -type structure that falls into this category and extends the electride concept into intermetallics. The confined electrons in the one-dimensional cavities are reflected by the characteristic channel bands in the electronic structure. Filling these free spaces with foreign oxygen atoms serves to engineer the band topology and increase the superconducting transition temperature to 10.5 K in Nb 5 Ir 3 O. Specific heat analysis indicates the appearance of low-lying phonons and two-gap s-wave superconductivity. Strong electron-phonon coupling is revealed to be the pairing glue with an anomalously large ratio between the superconducting gap Δ 0 and T c , 2Δ 0 /k B T c = 6.12. The general rule governing the formation of electrides concerns the structural stability against the cation filling/extraction in the channel site.

show abstract

Section: Introductionmentioning

confidence: 79%

“…Meanwhile, the low-temperature superconductivity is found to vanish gradually when the tetragonal phase diminishes from the XRD patterns; consistent with previous findings. 27 This is illustrative of their competing relationship. Thus, the higher T c is from hexagonal Nb 5 exhibits the highest T c .…”

Section: Synthesis and Band Structuresmentioning

confidence: 99%

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Rhenium-molybdenum alloys in the phase and the A15 structure as well as the Re-W hcp alloy system have been studied because of their superconducting properties. [6][7][8] Tungsten has been suggested as armor material in plasma facing components in future fusion devices. This has increased the interest in the Re-W system because the heavy neutron irradiation from the fusion process transforms W atoms into Re.…”

Section: Introductionmentioning

confidence: 99%

Dynamical and thermodynamical instabilities in the disorderedRexW1−xsystem

1999

View full text Add to dashboard Cite

The dynamical and thermodynamical stability of the bcc and fcc disordered Re x W 1Ϫx system is studied within the density-functional theory. The configurational part of the free energy is obtained from ab initio electron structure calculations together with the cluster expansion and the cluster variation formalism. Electronic excitations are accounted for through the temperature-dependent Fermi-Dirac distribution. The lattice dynamics of Re and W is studied using the density-functional linear-response theory. The calculated dispersion curves show that fcc Re is dynamically stable while bcc Re exhibits phonon instabilities in large parts of the Brillouin zone, similar to previous results for fcc W. Interestingly, the phonon dispersion curves for fcc Re show pronounced phonon anomalies characteristic of superconductors such as TaC and NbC. Due to the instabilities in bcc Re and fcc W the vibrational entropy, and therefore the free energy, is undefined. In order to predict the regions where the disordered Re x W 1Ϫx alloy is unstable we calculate the phonon dispersion curves in the virtual crystal approximation. Then we apply a concentration-dependent nonlinear interpolation to the force constants, which are calculated through a Born-von Kármán fit to the ab initio obtained dynamical matrices. The vibrational free energy is calculated in the stable regions for the phases as a function of concentration. The complete analysis gives a region where the bcc phase would become thermodynamically unstable towards a phase decomposition into disordered bcc and fcc phases.

show abstract

“…The impurity phase is assigned as Nb 3 Ir 2 -Nb 3 Pt 2 solid solution. The amount of Nb 3 Ir 2 , which is a superconductor [10] with T c ∼ 2.3 K, in x = 0 sample is rather large, but the T c is below the our lowest measurement temperature, and the impurity phase would have no influence on our experimental results. With increasing x, the peak positions with Miller indices (h k 0) and (0 0 l) shift to lower and higher 2θ angles, respectively.…”

Section: Resultsmentioning

confidence: 52%

Superconductivity in Nb₅Ir₃₋_xPt_xO

Kitagawa

Hamamoto

2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

View full text Add to dashboard Cite

We have investigated the superconducting critical temperature T c of solid solution Nb 5 Ir 3−x Pt x O with the Ti 5 Ga 4-type structure. The both end-members of Nb 5 Ir 3 O and Nb 5 Pt 3 O are reported to be superconductors with T c of 10.5 K and 3.8 K, respectively. Particularly Nb 5 Ir 3 O is considered as a two-gap superconductor. The entire series of alloy hold the Ti 5 Ga 4-type structure and show the linear x dependence of lattice parameters. On the other hand, a nonlinear T c vs x plot was obtained, suggesting that T c is not determined by only lattice parameters. The experimental result is discussed based on the Matthias rule and compared with those of the other two-gap superconductors such as MgB 2 , Mo 8 Ga 41 and Nb 3 Sn.

show abstract

Superconductivity in Mo-Re and Nb-IrσPhases

Cited by 29 publications

References 17 publications

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

Dynamical and thermodynamical instabilities in the disorderedRexW1−xsystem

Superconductivity in Nb₅Ir₃₋_xPt_xO

Contact Info

Product

Resources

About

Superconductivity in Mo-Re and Nb-IrσPhases

Cited by 29 publications

References 17 publications

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

Dynamical and thermodynamical instabilities in the disorderedRexW1−xsystem

Superconductivity in Nb5Ir3−xPtxO

Contact Info

Product

Resources

About

Superconductivity in Nb₅Ir₃₋_xPt_xO