Ultrafast Laser Induces Macroscopic Symmetry-Breaking of Diamond Color Centers

TL;DR

This study uses real-time density functional theory to reveal ultrafast symmetry-breaking and coupled electron-phonon-spin dynamics in diamond nitrogen-vacancy centers, advancing understanding of their microscopic behavior.

Contribution

It provides the first direct time-resolved visualization of ultrafast symmetry-breaking and coupled dynamics in nitrogen-vacancy centers using advanced simulations.

Findings

Laser excitation induces $C_{3v}$-symmetry breaking charge ordering within 100 fs.

Ionic motion causes symmetric oscillations and Jahn-Teller distortions with $C_{3v}$ symmetry breaking.

Nonlocal coherent phonons propagate through the diamond lattice at sound velocity, carrying symmetry-breaking information.

Abstract

The negatively charged nitrogen-vacancy center is a leading quantum platform due to its excellent spin coherence and stable interactions. Understanding its ultrafast dynamics is crucial for quantum applications but presents significant challenges for both experimental characterization and atomic-scale modeling. Here, we employ real-time time-dependent density functional theory to investigate the coupled electron-phonon-spin dynamics in negatively charged nitrogen-vacancy centers. Laser excitation promotes minority-spin electrons within 100~fs, establishing a $C_{3v}$-symmetry breaking charge ordering. Subsequently, ionic motion on the potential energy surface of the excited electrons generates both symmetric oscillations of carbon-nitrogen bonds and dynamic Jahn-Teller distortions with a $C_{3v}$-symmetry breaking. These distortions subsequently induce nonlocal coherent phonons in the diamond lattice, which propagate with the $C_{3v}$-symmetry breaking at the sound velocity ($\sim$2~\AA/fs). Our simulations provide direct time-resolved visualization of these processes, offering novel insights into the microscopic interplay of electrons, phonons, and spins in nitrogen-vacancy centers.