Reconstructing the bulk Fermi surface and the superconducting gap properties from Neutron Scattering experiments

TL;DR

This paper introduces an analytical method to derive bulk electronic properties, including Fermi surface and superconducting gap, from neutron scattering spectra, offering a bulk-sensitive alternative to surface techniques like ARPES and STM.

Contribution

The paper presents a novel, model-independent inversion technique to extract bulk electronic properties from neutron scattering data in unconventional superconductors.

Findings

Successfully reconstructs Fermi surface dispersion from INS spectra.

Reveals superconducting gap properties through spectral inversion.

Applicable to various materials, providing bulk electronic insights.

Abstract

We develop an analytical tool to extract bulk electronic properties of unconventional superconductors through inelastic neutron scattering (INS) spectra. Since the spin excitation spectrum in the superconducting (SC) state originates from Bogoliubov quasiparticle scattering associated with Fermi surface nesting, its energy-momentum relation--the so called `hour-glass' feature--can be inverted to reveal the Fermi momentum dispersion of the single-particle spectrum as well as the corresponding SC gap function. The inversion procedure is analogous to the quasiparticle interference (QPI) effect in scanning tunneling microscopy (STM). Whereas angle-resolved photoemission spectroscopy (ARPES) and STM provide surface sensitive information, our inversion procedure provides bulk electronic properties. The technique is essentially model independent and can be applied to a wide variety of materials.