Electronic band structure of a nodal line semimetal candidate ErSbTe

TL;DR

This study investigates the electronic structure and magnetic properties of ErSbTe, a candidate nodal line semimetal, using ARPES and theoretical calculations, revealing key features of its band structure and phase transitions.

Contribution

It provides the first detailed ARPES and theoretical analysis of ErSbTe, highlighting the effects of spin orbit coupling and nonsymmorphic symmetry on its electronic bands.

Findings

Electronic bands cross the Fermi energy along GX direction.

Paramagnetic to antiferromagnetic transition at ~1.94 K.

Diamond shaped Fermi surface observed.

Abstract

The LnSbTe family is well known for hosting a plethora of intriguing characteristics stemming from its crystalline symmetry, magnetic structure, 4f electronic correlations and spin orbit coupling (SOC) phenomena. In this paper, we have systematically studied the bulk electrical and thermodynamic properties and electronic structure of the nodal line semimetal candidate ErSbTe using angle resolved photoemission spectroscopy (ARPES) corroborated with first principles based theoretical band structure calculations with and without considering the effect of SOC, a critical factor dictating the band degeneracy which depends on the choice of the Ln atom. Corroborative temperature dependent susceptibility, electrical resistivity and thermodynamic measurements, coherently exhibit paramagnetic to antiferromagnetic phase transition approximately at 1.94 K, and another sharp anomaly at 1.75 K. The zero field cooled resistivity measurement does not show the characteristic hump like feature in the other LnSbTe materials. The electronic band structure of ErSbTe, exhibits a diamond shaped Fermi surface. Along the high symmetry direction GX, electronic bands are projected to cross over the Fermi energy, necessitated by the nonsymmorphic symmetry of the system. The other crossing along this direction is gapped, which evolves along the momentum space reaching its maximum along the GM direction.