Dominant Two-Dimensional Electron-Phonon Interactions in the Bulk Dirac Semimetal Na<sub>3</sub>Bi.

Desai, Dhruv C; Park, Jinsoo; Zhou, Jin-Jian; Bernardi, Marco · Nano Lett · 2023

basic_science · Level V

Where this comes from

Abstract

Bulk Dirac semimetals (DSMs) exhibit unconventional transport properties and phase transitions due to their peculiar low-energy band structure, yet the electronic interactions governing nonequilibrium phenomena in DSMs are not fully understood. Here we show that electron-phonon (<i>e</i>-ph) interactions in a prototypical bulk DSM, Na<sub>3</sub>Bi, are predominantly two-dimensional (2D). Our first-principles calculations reveal a 2D optical phonon with strong <i>e</i>-ph interactions associated with in-plane vibrations of Na atoms. We show that this 2D mode governs <i>e</i>-ph scattering and charge transport in Na<sub>3</sub>Bi and induces a dynamical phase transition to a Weyl semimetal. Our work advances the quantitative analysis of electron interactions in Na<sub>3</sub>Bi and reveals a dominant low-dimensional interaction in a bulk Dirac semimetal.