Fermi surface and light quasi particles in hourglass nodal chain metal \b{eta}-ReO2

TL;DR

This study uses quantum oscillation measurements to confirm the presence of an hourglass nodal chain electronic structure in {eta}-ReO2, revealing small Fermi surfaces with linear dispersion and very light quasiparticles.

Contribution

First experimental verification of the hourglass nodal chain in {eta}-ReO2 through quantum oscillation measurements aligning with theoretical predictions.

Findings

Observation of small Fermi surfaces with light effective mass

Confirmation of hourglass nodal chain near Fermi energy

Quantum oscillations match first-principles calculations

Abstract

Quantum oscillations in magnetic torque and electrical resistivity were measured to investigate the electronic structure of \b{eta}-ReO2, a candidate hourglass nodal chain metal (Dirac loop chain metal). All the de Haas-van Alphen oscillation branches measured at 30 mK in magnetic fields of up to 17.5 T were consistent with first-principles calculations predicting four Fermi surfaces (FSs). The small-electron FS of the four FSs exhibited a very small cyclotron mass, 0.059 times that of the free electrons, which is likely to be related to the linear dispersion of the energy band. The consistency between the quantum oscillation results and band calculations indicates the presence of the hourglass nodal chain predicted for \b{eta}-ReO2 in the vicinity of the Fermi energy.