Th<sub>2</sub>NiC<sub>2</sub>: a low density of states superconductor

Machado, A. J. S.; Grant, Ted; Fisk, Z.

doi:10.1088/0953-2048/25/4/045010

Cited by 5 publications

(1 citation statement)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Antiperovskite MgCNi 3 11 with T c = 8 K occurs with E F lying in a narrow and extremely sharp van Hove singularity, 12 where superconductivity competes strongly with ferromagnetic tendencies in a manner that is not typical of other Ni-based superconductors. Heusler compounds such as ZrNi 2 Ca which contain no C or B metalloid atom, and which are more often magnetically ordered when based on 3d transition metals, superconduct typically around T c ∼ 3K.…”

mentioning

confidence: 99%

Electronic fine structure in the nickel carbide superconductor Th2NiC2

Quan

Pickett

2013

Phys. Rev. B

View full text Add to dashboard Cite

The recently reported nickel carbide superconductor, body centered tetragonal I4/mmm Th2NiC2 with Tc = 8.5 K increasing to 11.2 K upon alloying Th with Sc, is found to have very fine structure in its electronic spectrum, according to density functional based first principles calculations. The filled Ni 3d band complex is hybridized with C 2p and Th character to and through the Fermi level (E f ), and a sharply structured density of states arises only when spin-orbit coupling is included, which splits a zone-center degeneracy leaving a very flat band edge lying at the Fermi level. The flat part of the band corresponds to an effective mass m * z → ∞ with large and negative m * x = m * y . Although the region over which the effective mass characterization applies is less than 1% of the zone volume, it yet supplies of the order of half the states at (or just above) the Fermi level. The observed increase of Tc by hole-doping is accounted for if the reference as-synthesized sample is minutely hole-doped, which decreases the Fermi level density of states and will provide some stabilization. In this scenario, electron doping will increase the Fermi level density of states and the superconducting critical temperature. Vibrational properties are presented, and enough coupling to the C-Ni-C stretch mode at 70 meV is obtained to imply that superconductivity is electron-phonon mediated.

show abstract

mentioning

confidence: 99%

Electronic fine structure in the nickel carbide superconductor Th2NiC2

Quan

Pickett

2013

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

Actinides: Superconducting Materials

Ott

Fisk

2018

Encyclopedia of Inorganic and Bioinorganic Chemistry

View full text Add to dashboard Cite

In comparison with metallic elements, whose conduction electrons derive from atomic s‐, p‐, and d‐orbitals, superconductivity of metals with itinerant electrons from atomic f‐orbitals is a rather scarce phenomenon. This article on superconductivity of the heaviest metals intends to demonstrate that this indeed is the case. The topic is, however, of interest because these metals and, in particular their compounds, often adopt unconventional superconducting phases with new and therefore exciting properties that are not yet fully understood. In some cases, superconductivity competes or even co‐exists with other long‐range order phenomena, demonstrating that subtle details in the electronic structure and the interaction of the electrons among themselves and/or with other excitations of structural or magnetic character have to be considered.

show abstract