Strain-controlled topology and quantum control at a cubic Ce3+ crystal-field crossing
Abstract
Field-tuned crystal-field crossings provide a route to synthetic topology in localized rare-earth degrees of freedom when symmetry-resolved perturbations can independently control the crossing states. Here we show that a field-induced crossing in cubic Ce3+ has precisely this structure. For B∥[001], the crossing is protected by a twofold rotation, while the T2g shears εxz and εyz break that protection and mix the two states through orthogonal pseudospin components. Together with magnetic-field detuning, these controls generate an isolated diabolical point with unit-magnitude Chern charge in a three-dimensional parameter space. Using the CeTe crystal-field scale gives an ideal single-ion crossing near $35.5$ T. A calibrated point-charge calculation gives a representative projected shear coupling |αT2g|≃18.1 meV per unit tensor strain, corresponding to gaps of $0.036$ and $0.072$ meV for tensor shears of 0.10% and 0.20%. We identify the associated elastic and magnetic signatures, discuss the limitations of the electrostatic estimate in a hybridizing Ce compound, and determine the adiabatic and coherence requirements for cyclic geometric control. The result is a symmetry-based framework that connects high-field crystal-field reconstruction, strain response, and parameter-space topology in rare-earth systems.
Related
- Electron-phonon control of obstructed and quantum spin Hall topology in an altermagnet
- Spacetime topology and geometry in JT Gravity from non-crossing permutations
- Crossing the 12,000-atom barrier with heterogeneous quantum-classical supercomputing: quantum chemistry of protein-ligand complexes
- Three-Dimensional Topology from Stacking-Controlled Umklapp Scattering in Large-Angle Twisted Graphite
- Deep Generative Crystal Structure Prediction: A Benchmark Study and a Controlled Test of Prototype Dependence
BibTeX
@misc{ghosh2026straincontrolled,
title = {{Strain-controlled topology and quantum control at a cubic Ce$^3+$ crystal-field crossing}},
author = {A. Ghosh and J. T. Haraldsen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.30737},
eprint = {2609.30737},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.30737},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Strain-controlled topology and quantum control at a cubic Ce^3+ crystal-field crossing
AU - A. Ghosh
AU - J. T. Haraldsen
PY - 2026
DA - 2026/09/25
PB - arXiv
DO - 10.48550/arxiv.2609.30737
UR - https://arxiv.org/abs/2609.30737
AB - Field-tuned crystal-field crossings provide a route to synthetic topology in localized rare-earth degrees of freedom when symmetry-resolved perturbations can independently control the crossing states. Here we show that a field-induced crossing in cubic Ce^3+ has precisely this structure. For B∥[001], the crossing is protected by a twofold rotation, while the T_2g shears ε_xz and ε_yz break that protection and mix the two states through orthogonal pseudospin components. Together with magnetic-field detuning, these controls generate an isolated diabolical point with unit-magnitude Chern charge in a three-dimensional parameter space. Using the CeTe crystal-field scale gives an ideal single-ion crossing near $35.5$ T. A calibrated point-charge calculation gives a representative projected shear coupling |α_T_2g|≃18.1 meV per unit tensor strain, corresponding to gaps of $0.036$ and $0.072$ meV for tensor shears of 0.10% and 0.20%. We identify the associated elastic and magnetic signatures, discuss the limitations of the electrostatic estimate in a hybridizing Ce compound, and determine the adiabatic and coherence requirements for cyclic geometric control. The result is a symmetry-based framework that connects high-field crystal-field reconstruction, strain response, and parameter-space topology in rare-earth systems.
ER -