Electron-hole tunnelling probed in de Haas - van Alphen oscillations in the (double) Dirac semimetal NbTe$_4$

TL;DR

This study investigates the electronic structure of NbTe$_4$, a double Dirac semimetal, using DFT calculations and de Haas-van Alphen oscillation analysis, revealing magnetic breakdown orbits indicative of complex charge carrier interactions.

Contribution

It provides new insights into NbTe$_4$'s electronic properties and demonstrates the use of dHvA oscillations to probe magnetic breakdown in a double Dirac semimetal.

Findings

Identification of magnetic breakdown orbits between electron and hole pockets.

Confirmation of the double Dirac points in NbTe$_4$'s band structure.

Insights into charge density wave effects on electronic structure.

Abstract

NbTe$_4$ undergoes multiple charge density wave transitions that have attracted great interest in this material for decades. Previous work has shown that the crystal obtains the space group P4/ncc (130) at temperatures below 50K which allows for the existence of eightfold degenerate double Dirac points in the band structure. We provide insights into the electronic structure of this material through density functional theory (DFT) calculations, and a rotation study of de Haas - van Alphen (dHvA) oscillations in the magnetic torque. We find that NbTe$_4$ exhibits magnetic breakdown orbits between electron and hole pockets.