We report on terahertz (THz) electron paramagnetic resonance generalized spectroscopic ellipsometry (THz-EPR-GSE). Measurements of the field and frequency dependencies of the magnetic response due to the spin transitions associated with the nitrogen defect in 4H-SiC are shown as an example. THz-EPR-GSE dispenses with the need of a cavity, permits independently scanning field and frequency parameters, and does not require field or frequency modulation. We investigate spin transitions of hexagonal (h) and cubic (k) coordinated nitrogen including coupling with its nuclear spin (I=1), and we propose a model approach for the magnetic susceptibility to account for the spin transitions. From the THz-EPR-GSE measurements we can fully determine the polarization properties of the spin transitions and we obtain g and hyperfine splitting parameters using magnetic field and frequency dependent Lorentzian oscillator lineshape functions. We propose frequency-scanning THz-EPR-GSE as a new and versatile method to study properties of spins in solid state materials.
@article{arxiv.2201.06695,
title = {Terahertz electron paramagnetic resonance generalized spectroscopic ellipsometry: The magnetic response of the nitrogen defect in 4H-SiC},
author = {Mathias Schubert and Sean Knight and Steffen Richter and Philipp Kühne and Vallery Stanishev and Alexander Ruder and Megan Stokey and Rafal Korlacki and Klaus Irmscher and Petr Neugebauer and Vanya Darakchieva},
journal= {arXiv preprint arXiv:2201.06695},
year = {2022}
}