Robust Luttinger liquid state of 1D Dirac fermions in a van der Waals system Nb$_9$Si$_4$Te$_{18}$

TL;DR

This paper demonstrates the presence of a robust Tomonaga-Luttinger liquid state in 1D Dirac fermions within a van der Waals material, Nb$_9$Si$_4$Te$_{18}$, highlighting strong electron interactions and defect resilience.

Contribution

It reports the experimental observation of TLL behavior in a 1D Dirac fermion system within a van der Waals material, showing robustness against defects and potential for tunable non-Fermi liquid physics.

Findings

Tunneling conductance follows a power law with temperature scaling.

Luttinger parameter of ~0.15 indicates strong electron-electron interactions.

TLL behavior remains stable despite atomic-scale defects.

Abstract

We report on the Tomonaga-Luttinger liquid (TLL) behavior in fully degenerate 1D Dirac fermions. A ternary van der Waals material Nb$_9$Si$_4$Te$_{18}$ incorporates in-plane NbTe$_2$ chains, which produce a 1D Dirac band crossing Fermi energy. Tunneling conductance of electrons confined within NbTe2 chains is found to be substantially suppressed at Fermi energy, which follows a power law with a universal temperature scaling, hallmarking a TLL state. The obtained Luttinger parameter of ~0.15 indicates strong electron-electron interaction. The TLL behavior is found to be robust against atomic-scale defects, which might be related to the Dirac electron nature. These findings, as combined with the tunability of the compound and the merit of a van der Waals material, offer a robust, tunable, and integrable platform to exploit non-Fermi liquid physics.