How to determine Fermi vectors by angle resolved photoemission?

TL;DR

This paper presents a new high-resolution ARPES method for accurately determining Fermi vectors, especially in narrow band systems, demonstrated on TiTe2 data.

Contribution

The authors develop a reliable ARPES-based technique for Fermi vector determination that reduces uncertainties compared to traditional criteria.

Findings

Traditional criteria can lead to large uncertainties in narrow band systems.

The new method improves accuracy in Fermi vector determination.

Application to TiTe2 validates the method's effectiveness.

Abstract

Angle resolved photoemission spectroscopy (ARPES) has been commonly applied to evaluate the shape of Fermi surfaces by employing simple criteria for the determination of the Fermi vector k_F parallel to the surface such as maximum photoemission intensity at the Fermi level or discontinuity in the momentum distribution function. Here we show that these criteria may lead to large uncertainties in particular for narrow band systems. We develop a reliable method for the determination of Fermi vectors employing high resolution ARPES at different temperatures. The relevance and accuracy of the method is discussed on data of the quasi two dimensional system TiTe_2.