# Quasiparticle interference and resonant states in normal and superconducting line nodal semimetals

## TL;DR

This paper investigates impurity effects in line nodal semimetals, revealing extended quasiparticle interference patterns and altered impurity behavior in surface states of superconducting phases, advancing understanding of surface scattering phenomena.

## Contribution

It introduces the analysis of impurity scattering and interference patterns in surface states of line nodal semimetals, highlighting unique behaviors in the superconducting regime.

## Key findings

- Quasiparticle interference patterns become extended due to surface scattering.
- Conventional impurity behavior in d-wave superconductors is modified on the semimetal surface.
- Impurity effects are significantly different in the quasi flat band limit.

## Abstract

We study impurity scattering in the normal and d-wave superconducting states of line nodal semimetals and show that, due to additional scattering phase space available for impurities on the surface, the quasiparticle interference pattern acquires an extended character instead of a discrete collection of delta function peaks. Moreover, using the T-matrix formalism, we demonstrate that the conventional behavior of a scalar impurity in a d-wave superconductor breaks down on the surface of a line nodal semimetal in the quasi flat band limit.