Temperature-dependent collective excitations in the three-dimensional Dirac system ZrTe5

Le résumé fourni par la source

Zirconium pentatelluride $({\mathrm{ZrTe}}_{5})$, a system with a Dirac linear band across the Fermi level and anomalous transport features, has attracted considerable research interest for it is predicted to be located at the boundary between strong and weak topological insulators separated by a topological semimetal phase. However, the experimental verification of the topological phase transition and the topological ground state in ${\mathrm{ZrTe}}_{5}$ is full of controversies, mostly due to the difficulty of precisely capturing the small gap evolution with single-particle band structure measurements. Alternatively, the collective excitations of electric charges, known as plasmons, in Dirac systems exhibiting unique behavior can well reflect the topological nature of the band structure. Here, using reflective high-resolution electron energy loss spectroscopy (HREELS), we investigate the temperature-dependent collective excitations of ${\mathrm{ZrTe}}_{5}$, and discover that the plasmon energy in ${\mathrm{ZrTe}}_{5}$ is proportional to the $1/3$ power of the carrier density $n$, which is a unique feature of plasmons in three-dimensional Dirac systems or hyperbolic topological insulators. Based on this conclusion, the origin of the resistivity anomaly of ${\mathrm{ZrTe}}_{5}$ can be attributed to the temperature-dependent chemical potential shift in extrinsic Dirac semimetals.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.