E. S. Zijlstra

CePt3Si: An unconventional superconductor without inversion center

Most superconducting materials have an inversion center in their crystal lattices. One of few exceptions is the recently discovered heavy-fermion superconductor

Electronic structure, electron–phonon coupling and superconductivity of isotypic noncentrosymmetric crystals Li2Pd3B and Li2Pt3B

{mathrm{CePt}}_{3}mathrm{Si}

Negative valence of Mn in i-Al–Pd–Mn quasicrystals

[E. Bauer et al., Phys. Rev. Lett. 92, 027003 (2004)]. In this paper, we analyze the implications of the lack of inversion symmetry for the superconducting pairing. We show that the order parameter is an odd function of momentum, and that there always are lines of zeros in the excitation energy gap for one-component order parameters, which seems to agree with the experimental data. The superconducting phase can be nonuniform, even without external magnetic field, due to the presence of unusual gradient terms in the Ginzburg-Landau free energy. Also, we performed ab initio electronic structure calculations for

Electronic states in 1 ∕ 1 Cd 6 Yb and 1 ∕ 1 Cd 6 Ca : Relativistic, correlation, and structural effects

{mathrm{CePt}}_{3}mathrm{Si},

Atomic structure, Electronic States, and Stability of Icosahedral Quasicrystals

which showed that the spin-orbit coupling in this material is strong, and the degeneracy of the bands is lifted everywhere except along some high symmetry lines in the Brillouin zone.

Origin of anisotropic nonmetallic transport in the Al80 Cr15 Fe5 decagonal approximant

Abstract Electronic structure of recently discovered isotypic ternary borides Li 2 Pd 3 B and Li 2 Pt 3 B, with noncentrosymmetric crystal structures, is studied with a view to understanding their superconducting properties. Estimates of the Fermi surface averaged electron–phonon matrix element and Hopfield parameter are obtained in the rigid ion approximation of Gaspari and Gyorffy [G.D. Gaspari, B.L. Gyorffy, Phys. Rev. Lett. 28 (1972) 801]. The contribution of the lithium atoms to the electron–phonon coupling is found to be negligible, while both boron and palladium atoms contribute equally strongly to the Hopfield parameter. There is a significant transfer of charge from lithium, almost the entire valence charge, to the B–Pd(Pt) complex. The electronic structure and superconducting properties of Li 2 Pd 3 B, thus, can be understood from the viewpoint of the compound being composed of a connected array of B–Pd tetrahedra decoupled from the backbone of Li atoms, which are connected by relatively short bonds. Our results suggest that conventional s-wave electron–phonon interaction without explicit consideration of SO coupling can explain qualitatively the observed T c in Li 2 Pd 3 B. However, such an approach is likely to fail to describe superconductivity in Li 2 Pt 3 B.

Extrinsic origin of the insulating behavior of polygrain icosahedral Al-Pd-Re quasicrystals

The electronic structure of a modified version of the Quandt–Elser model of i-Al70.8Pd21.5Mn7.7 is studied by the full-potential linearized augmented plane wave method. Inspection of the electronic charge density and an analysis based on Baders concept of atoms in a molecule reveal a charge transfer from the Al atoms to Mn. It is argued that this charge transfer is responsible for the negative valence of Mn in i-Al–Pd–Mn quasicrystals.

Ab initio study of icosahedral Al-Pd-Mn quasicrystals : Structural model, electric field gradients, and negative valence of Mn

The electronic structure of the rational approximants

The effect of thermal treatment on the magnetic state and cluster-related disorder of icosahedral Al–Pd–Mn quasicrystals

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