Scattering Due to Non-magnetic Disorder in 2D Anisotropic d-wave High T<sub>c</sub> Superconductors

Abstract

Inspired by the studies on the influence of transition metal impurities in high Tc superconductors and what is already known about nonmagnetic suppression of T c in unconventional superconductors, we set out to investigate the behavior of the nonmagnetic disordered elastic scattering for a realistic 2D anisotropic high T c superconductor with line nodes and a Fermi surface in the tight-binding approximation. For this purpose, we performed a detailed self-consistent 2D numerical study of the disordered averaged scattering matrix with nonmagnetic impurities and a singlet line nodes order parameter, varying the concentration and the strength of the impurities potential in the Born, intermediate and unitary limits. In a high T c anisotropic superconductor with a tight binding dispersion law averaging over the Fermi surface, including hopping parameters and an order parameter in agreement with experimental data, the tight-binding approximation reflects the anisotropic effects. In this study, we also included a detailed visualization of the behavior of the scattering matrix with different sets of physical parameters involved in the nonmagnetic disorder, which allowed us to model the dressed scattering behavior in different regimes for very low and high energies. With this study, we demonstrate that the scattering elastic matrix is affected by the non-magnetic disorder, as well as the importance of an order parameter and a Fermi surface in agreement with experiments when studying this effect in unconventional superconductors.

Quasi-point versus point nodes in Sr2RuO4, the case of a flat tight binding γ sheet

“…It resembles a gapless node points in unconventional superconductors (also it resembles the line nodes points model of high T c compounds we previously calculated for La 2−x Sr x CuO 4 in Ref. [29]). This intuitively means that the half filling ground state in the unitary limit gives point nodes and a flat dispersion law if the TB parameters are appropriately chosen.…”

“…However, as we recently reported [20], Born scattering does not play a role in the low temperature properties of Sr 2 RuO 4 it has a RPS window of ∆ 0 = 1.0 meV. At this point we also emphasize, that for the case of the lines nodes superconductor La 2−x Sr x CuO 4 , we reported that this compound can be numerically be in the Born limit with a RPS scattering window if ∆ 0 = 33.9 meV, for it we found another family of Wigner probabilistic distributions [20,29].…”

Non-magnetic tight binding disorder effects in the γ sheet of Sr2RuO4.

“…First we vary the inverse strength parameter c from 0 to 1 and second, we vary the value of the parameter Γ + from optimal to dilute doping in the function ω ω + i 0 + ). We finish our short report by comparing our findings with a line nodes tight binding analysis for High Tc compounds recently investigated using the same approach [18].…”

Tight-Binding Superconducting Phases in the Unconventional Compounds Strontium-Substituted Lanthanum Cuprate and Strontium Ruthenate

“…= (0.2, 0.4) meV and an electron-hole (eh) symmetry * , = + − , − . The order parameter corresponds to the supercoducting gap Δ , = Δ -, with an irreducible representation basis function -, = %cos − cos ) and the zero gap parameter Δ = 33.9 meV [8,9].…”

“…Since our primary goal is to visualize and describe briefly some properties of the three family of Wigner probabilistic distributions, we ought to emphasize that the whole analysis relays on the calculation of the function [9].…”