arXiv subjects

Elihu Abrahams

Publications and source records attributed to Elihu Abrahams.

41 records · Page 3Linked to original sources

arXiv1995

Interactions for odd-omega gap singlet superconductors

A class of singlet superconductors with a gap function $Δ({\bf k}, ω_n)$ which is {\it odd} in both momentum and Matsubara frequency was proposed recently \cite{ba}. To show an instability in the {\it odd} gap channel, a model phonon propagator was used with the $p$-wave interaction strength larger than the $s$-wave. We argue that the positive scattering matrix element entering the Eliashberg equations leads to a constraint on the relative strength of $p$- and $s$-wave interactions which inhibits odd pairing. However, a general spin dependent electron-electron interaction can satisfy all constraints and produce the odd singlet gap. A possibility which may lead to an odd gap is a strongly antiferromagnetically correlated system, such as a high-$T_c$ material.

cond-mat↗

arXiv1995

Properties of Odd Gap Superconductors

We discuss the class of superconductors which have pairing correlations which are odd in frequency, as introduced originally by Berezinskii and more recently by Balatsky and Abrahams. As follows from the equations of motion, a natural definition of the thermodynamic order parameter of the odd-pairing state is the expectation value of a composite operator which couples a Cooper pair to a spin or charge fluctuation. We use a model pairing hamiltonian to describe properties of the odd-pairing composite-operator condensate. We show that the superfluid stiffness is positive, we discuss superconductive tunneling with an ordinary superconductor and we derive other thermodynamic and transport properties.

cond-mat↗

arXiv1994

Odd time magnetic correlations and chiral spin nematics

The magnetic analog of odd-time superconducting order is introduced. It is shown that the classification of possible odd-time magnetic states admits the existence of a novel state - the chiral spin nematic - which is characterized by an odd-in-time spin-spin correlation function.The known example of the chiral spin liquid appears naturally in this approach. The equal-time correlation function of these odd-in-time states involves non-trivial three spin correlations.

cond-mat↗

arXiv1993

Properties of Odd Gap Superconductors

A new class of superconductors with the gap function {\it odd} under time reversal is considered. Some of the physical properties of these superconductors such as the Meissner effect, composite condensate, gapless spectrum and transition from the {\it odd} gap superconductor to the BCS state at lower temperatures are discussed.

cond-mat↗

arXiv1992

A novel class of singlet superconductors

A new class of singlet superconductors with a gap function $Δ(\bk, ω_n)$ which is {\it odd} in both momentum and Matsubara frequency is considered. Some of the physical properties of this superconductivity are discussed and it is argued that: i) the electron-phonon interaction can produce this kind of pairing, ii) in many cases there is no gap in the quasiparticle spectrum, iii) these superconductors will exhibit a Meissner effect.

cond-mat↗