Jahn-Teller-dynamics: Python package to determine vibronic interaction demonstrated on molecules and trigonal defect qubits
Description
Trigonal solid-state defects are often subjects of spontaneous symmetry breaking driven by the E⊗e Jahn-Teller effect, reflecting strong electron-phonon coupling. These systems, particularly paramagnetic defect qubits in solids are central for quantum technology applications, where accurate knowledge of their fine-structure parameters – shaped by the complex interplay of spin-orbit and electron-phonon interactions – is essential. We introduce the jahn - teller - dynamics package, a Python code that implements the first-principles approach of [Phys. Rev. X 8, {021063} (2018)] to accurately compute the spin-orbit-phonon entanglement in trigonal defects utilizing the output from density functional theory calculations (DFT) to predict fine-structure parameters of zero-phonon lines (ZPLs), including Zeeman shifts under external magnetic fields. We demonstrate its capabilities on negatively charged Group-IV–vacancy (G4V) defects in diamond: SiV-, GeV-, SnV-, PbV- and the neutral N3V0 defect in diamond, and the CH3O0 methoxy radical. Additionally, we implement a generic electron-phonon code that is capable entangling an arbitrary amount of (i) vibration modes and (ii) electronic levels by (iii) arbitrarily high order of vibronic interaction terms. Exemplarily, we demonstrate the Jahn-Teller multimode problem on the CH3O0 methoxy radical and the Pseudo Jahn-Teller case on the C4H4+ butatrien cation.