Dominant Two-Dimensional Electron-Phonon Interactions in the Bulk Dirac Semimetal Na₃Bi

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Bulk Dirac semimetals (DSMs) possess unique electronic properties due to their band structure.
• Understanding electron-phonon (e-ph) interactions is crucial for exploring nonequilibrium phenomena in DSMs.
• The nature of e-ph interactions in DSMs, particularly in materials like Na3Bi, remains incompletely characterized.

Purpose of the Study:

• To investigate the dimensionality and impact of electron-phonon interactions in the bulk Dirac semimetal Na3Bi.
• To elucidate the role of specific phonon modes in governing charge transport and phase transitions.
• To advance the quantitative analysis of electron interactions in Na3Bi.

Main Methods:

• First-principles calculations were employed to study the electronic band structure and phonon properties of Na3Bi.
• Analysis focused on identifying dominant electron-phonon coupling mechanisms and their spatial characteristics.
• Simulations explored the influence of these interactions on charge transport and potential phase transitions.

Main Results:

• Electron-phonon interactions in Na3Bi are predominantly two-dimensional (2D), driven by in-plane vibrations of Sodium (Na) atoms.
• A specific 2D optical phonon mode exhibits strong e-ph coupling.
• This 2D e-ph interaction significantly influences scattering, charge transport, and induces a dynamical transition to a Weyl semimetal phase.

Conclusions:

• The study reveals that low-dimensional interactions play a dominant role in bulk Dirac semimetals.
• The identified 2D electron-phonon mode is key to understanding charge transport and phase transitions in Na3Bi.
• This work provides a quantitative framework for analyzing electron interactions in Na3Bi and similar materials.