Effect of an electron-phonon interaction on the one-electron spectral weight of ad-wave superconductor

Abstract

Here we analyze the effects of an electron-phonon interaction on the one-electron spectral weight A(k, ω) of a d x 2 −y 2 superconductor. We study the case of an Einstein phonon mode with various momentum-dependent electron-phonon couplings and compare the structure produced in A(k, ω) with that obtained from coupling to the magnetic π-resonant mode. We find that if the strength of the interactions are adjusted to give the same renormalization at the nodal point, the differences in A(k, ω) are generally small but possibly observable near k = (π, 0).

Phononic self-energy effects and superconductivity in CaC6

“…The main properties of the spectral function in the superconducting state have been reported by Scalapino 5,6 and, more recently have also been studied using the ARPES experimental data [7][8][9] . However, to the best of our knowledge, no first-principles attempt has been made to study the effect of polarons in the superconducting state.…”

Angle and frequency dependence of self-energy from spin fluctuation mediated d-wave pairing for high temperature superconductors

“…As alluded in the introduction, this angle dependence of the peak energy may not be properly addressed in the approaches where a separable form of the off-diagonal self energy like φ(k, ω) = φ(ω)[cos(k x a) − cos(k y a)] or φ(k, ω) = φ(ω) cos(2θ), [12,7,4] or a phenomenological form of the spin susceptibility is assumed. For example, the separable form of the off-diagonal self-energy may give misleading results with regard to the angle dependence of an energy scale because the angle dependence was built in by hands.…”

“…[12] An interesting case is where the momentum sum covers the saddle point which usually occurs at (0, π). This introduces another energy scale in −Σ 2 (k, ω) from the van Hove singularity (VHS).…”

Tunneling spectra of strongly coupled superconductors: Role of dimensionality

“…26͒ but a phonon scenario was also put forward. 22,23 In the present work, we extend these approaches to three dimensions ͑3D͒ by means of an additional hopping t z describing the dispersion along the c axis, and we study the evolution of the strong-coupling features in the tunneling spectrum along the 2D to 3D transition on increasing t z . For simplicity we restrict to the spin-resonance scenario; the electron-phonon model can be treated along the same lines, and both models lead to the same main conclusions.…”

“…Among the new approaches introduced to study strongcoupling effects in HTS, some have focused on generalizing the classical formalism to the case of d-wave pairing, [19][20][21][22] still overlooking the dimensionality. Other models are strictly two dimensional ͑2D͒ and pay attention to the full electron dispersion, 7,8,17,[23][24][25] taking into account the singularities of N 0 ͑ ͒.…”