Vibronic and spin-orbit splitting in spectra of systems exhibiting Jahn-Teller-Effect

1973 ◽  
Vol 28 (3) ◽  
pp. 267-282 ◽  
Author(s):  
Peter Habitz ◽  
Wilhelm Hans Eugen Schwarz
Keyword(s):  
Teller Effect ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Jahn Teller ◽  
Jahn Teller Effect

Electron-phonon Coupling in the 4T2g Excited Electron State of Cs2GeF6:Mn4+

2005 ◽  
Vol 60 (1-2) ◽  
pp. 54-60
Author(s):  
N. M. Avram ◽  
M. G. Brika
Keyword(s):  
Energy Surface ◽  
Normal Modes ◽  
Coupling Constants ◽  
Octahedral Complex ◽  
Phonon Coupling ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Electron Phonon Coupling ◽  
Jahn Teller ◽  
Jahn Teller Effect

In the present paper we report on an analysis of the fine structure of the first excited quartet 4T2g of Mn4+ ions which occupy the octahedral site in the Cs2GeF6 host crystal. The dynamic 4T2g⊗(eg+t2g) Jahn-Teller effect is considered in details, including the Ham effect of the reduction of the spin-orbit splitting and displacements of the ligands due to the combined effect of the a1g and eg normal modes of the [MnF6]2− octahedral complex. The electron-phonon coupling constants are evaluated using the experimental spectroscopic data. The value of the Jahn-Teller stabilization energy EJT = 438 cm−1 for the considered complex is estimated from both the Ham effect and the potential energy surface of the 4T2g excited state.

Buckling on stanene: the role played by spin-orbit coupling and pseudo Jahn-Teller effect

MRS Advances ◽  
2017 ◽  
Vol 2 (29) ◽  
pp. 1563-1569 ◽  
Author(s):  
J. R. Soto ◽  
B. Molina ◽  
J. J. Castro
Keyword(s):  
Dft Calculations ◽  
Group Iv ◽  
Vibronic Coupling ◽  
Coupling Constants ◽  
Orbit Coupling ◽  
Teller Effect ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Jahn Teller ◽  
Jahn Teller Effect

ABSTRACTTwo-dimensional group IV layers beyond graphene, as silicene, germanene and the Sn-based stanene, have been recently synthesized by molecular beam epitaxy. Density Functional Theyory (DFT) calculations predict low-buckled structures for these 2D nanosheets, with a hexagonal honeycomb conformation, typical of the graphene-like surfaces. The buckling parameter δ increases from Si to Sn-based layers, with a maximum predicted of 0.92 Å for stanene. High-buckled structures for these materials resulted to be unstable. We have previously shown that for silicene and germanene, the origin of the buckled structure resides on the pseudo Jahn-Teller puckering distortion, resulting from non-adiabatic effects. It has been shown that hexagermabenzene, the single hexagonal unit of germanene, is subject to a strong vibronic coupling whose origin is the pseudo Jahn-Teller effect. This coupling resulted to be around ten times larger than the one obtained for hexasilabenzene. For stanene, an additional effect needs to be considered to understand the origin of buckling: the spin-orbit coupling (SOC). This SOC contributes to open an electronic band gap, enabling the use of these layers as nanoelectronic components. In this work, we present an analysis based on DFT in the Zeroth-Order Regular Approximation (ZORA) for both scalar relativistic and spin-orbit versions that quantify the influence of the spin-orbit coupling in the puckering of Sn6H6. Also, under the linear vibronic coupling model between the ground and the lowest excited states, we present the pseudo Jahn-Teller contribution. The scalar ZORA approximation is used to perform time-dependent DFT calculations to incorporate the low-energy excitations contributions. Our model leads to the determination of the coupling constants and predicts simultaneously the Adiabatic Potential Energy Surface behavior for the ground and excited states around the maximum symmetry point. These values allow us to compare the Jahn-Teller relevance in buckling with the other group IV layers.

scholarly journals Strong spin–orbit quenching via the product Jahn–Teller effect in neutral group IV qubits in diamond

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Christopher J. Ciccarino ◽  
Johannes Flick ◽  
Isaac B. Harris ◽  
Matthew E. Trusheim ◽  
Dirk R. Englund ◽  
...  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Group Iv ◽  
Teller Effect ◽  
Color Centers ◽  
Spin Orbit ◽  
Neutral Group ◽  
Theoretical Understanding ◽  
Jahn Teller ◽  
Jahn Teller Effect

Abstract Artificial atom qubits in diamond have emerged as leading candidates for a range of solid-state quantum systems, from quantum sensors to repeater nodes in memory-enhanced quantum communication. Inversion-symmetric group IV vacancy centers, comprised of Si, Ge, Sn, and Pb dopants, hold particular promise as their neutrally charged electronic configuration results in a ground-state spin triplet, enabling long spin coherence above cryogenic temperatures. However, despite the tremendous interest in these defects, a theoretical understanding of the electronic and spin structure of these centers remains elusive. In this context, we predict the ground-state and excited-state properties of the neutral group IV color centers from first principles. We capture the product Jahn–Teller effect found in the excited state manifold to second order in electron–phonon coupling, and present a nonperturbative treatment of the effect of spin–orbit coupling. Importantly, we find that spin–orbit splitting is strongly quenched due to the dominant Jahn–Teller effect, with the lowest optically-active 3Eu state weakly split into ms-resolved states. The predicted complex vibronic spectra of the neutral group IV color centers are essential for their experimental identification and have key implications for use of these systems in quantum information science.

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