Superconductivity and Intralayer Structure in Potassium Amalgam-Gic

1982 ◽  
Vol 20 ◽  
Author(s):  
G. Timp ◽  
B.S. Elman ◽  
M.S. Dresselhaus ◽  
P. Tedrow
Keyword(s):  
Transition Temperature ◽  
Fermi Surface ◽  
Electronic Properties ◽  
Raman Spectra ◽  
Basal Plane ◽  
High Frequency ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Lattice Fringe ◽  
Structural Lattice

ABSTRACTWe report on the structural, lattice and electronic properties of stage 1,2,3 potassium-amalgam GIG and the relation of these properties to the observed superconducting transition temperature. The ultramicrostructure of the intercalant domains is investigated using lattice fringe imaging. Our observation of macroscopic (√3×√3),(2×2) and (√3×2) domains is consistent with the basal plane zonefolded phenomena observed in the Raman spectra. Shubnikovde Haas measurements of the Fermi surface show high frequency (>1000 T) oscillations in stage 2, identified with the intercalant band.

scholarly journals Distinct superconducting properties and hydrostatic pressure effects in 2D α- and β-Mo2C crystal sheets

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yunjie Fan ◽  
Chuan Xu ◽  
Xiang Liu ◽  
Chao Ma ◽  
Yuewei Yin ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Hydrostatic Pressure ◽  
Electronic Properties ◽  
Superconducting Transition Temperature ◽  
Important Influence ◽  
Pressure Effects ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Disordered Carbon

Abstract Recently, 2D Mo2C, a new member of the MXene family, has attracted much attention due to the exotic superconducting properties discovered in 2D α-Mo2C. Here, not only 2D α-Mo2C but also 2D β-Mo2C crystal sheets with distinct disordered carbon distributions were successfully grown. 2D β-Mo2C shows a much stronger superconductivity than 2D α-Mo2C, and their superconductivities have different hydrostatic pressure responses. The superconducting transition temperature Tc of 2D α-Mo2C shows a dome-shaped profile under pressure, implying the existence of two competing effects arising from phononic and electronic properties, while for 2D β-Mo2C, Tc decreases monotonically with increasing pressure, possibly due to phonon stiffening. These results indicate that the electronic properties have a more important influence on the superconductivity in 2D α-Mo2C compared to 2D β-Mo2C. The ordered and disordered carbon distributions in 2D α-Mo2C and β-Mo2C, respectively, may be the underlying origin for their different electronic and superconducting properties.

Two-dimensional stoichiometric boron carbides with unexpected chemical bonding and promising electronic properties

2018 ◽  
Vol 6 (7) ◽  
pp. 1651-1658 ◽  
Author(s):  
Dong Fan ◽  
Shaohua Lu ◽  
Yundong Guo ◽  
Xiaojun Hu
Keyword(s):  
Transition Temperature ◽  
Electronic Properties ◽  
Young’S Modulus ◽  
Chemical Bonding ◽  
Superconducting Transition Temperature ◽  
Young's Modulus ◽  
Two Dimensional ◽  
Superconducting Transition ◽  
Pyramidal Geometry ◽  
Bonding Patterns

We identify two B–C bonding patterns: pyramidal-geometry tetra-coordinated and hexa-coordinated sp2carbon moiety; B4C3has an ultrahigh Young's modulus that can even outperform graphene; the B2C sheet is metallic with a relatively high superconducting transition temperature (Tc≈ 21.20 K).

PHONON BEHAVIOR OF Y-Ba-Cu-O SUPERCONDUCTOR AND SEMICONDUCTOR

1987 ◽  
Vol 01 (02) ◽  
pp. 409-412 ◽  
Author(s):  
Jinghui Ruan ◽  
Jizhou Li ◽  
Ansun Yu ◽  
Shu Gan ◽  
Tonghua Yang ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Density Of States ◽  
High Frequency ◽  
Superconducting Transition Temperature ◽  
Low Frequency ◽  
Scattering Method ◽  
Phonon Density ◽  
Superconducting Transition ◽  
Phonon Density Of States ◽  
Neutron Inelastic Scattering

The generalized phonon density of states of Y-Ba-Cu-O superconductor and semiconductor has been measured by neutron inelastic scattering method. The results show that the decrease or disappearance of high frequency modes and the increase of low frequency modes may have some relations to the high superconducting transition temperature

KONDO IMPURITY MODEL FOR ANOMALOUS RESISTIVITY OF IMPURE Zr-Cu SUPERCONDUCTOR

2002 ◽  
Vol 16 (25) ◽  
pp. 3817-3835 ◽  
Author(s):  
A. K. MONDAL ◽  
S. K. ROY
Keyword(s):  
Transition Temperature ◽  
Fermi Surface ◽  
Density Of States ◽  
Superconducting Transition Temperature ◽  
Kondo Temperature ◽  
Anomalous Resistivity ◽  
Superconducting Transition ◽  
Impurity Model ◽  
Good Agreement

Resistivity expressions are derived for disordered Zr 50- Cu 50 alloy considering the Kondo impurity model with extended BCS term to check the anomaly appearing above superconducting transition temperature as observed. The resistivity behaviors are discussed below and above the Kondo temperature and compared with the anomalies reported experimentally. Very good agreement between theoretical and experimental, natures of the resistivity curves are reported with a change in density of states (DOS) at the Fermi surface.

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

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