Large in-plane optical anisotropy in epitaxial CrN(113) films
Abstract
CrN, a transition-metal nitride crystallizing in the cubic rocksalt structure, exhibits a unique combination of mechanical robustness, semiconducting behavior, and thermoelectric functionality. To date, however, CrN has been synthesized primarily as polycrystalline material or as epitaxial films grown along high-symmetry orientations such as (001) and (111). Here, we prepare epitaxial CrN(113) films on AlN(11\bar{2}2) templates by plasma-assisted molecular beam epitaxy. The low-symmetry interface and highly direction dependent lattice mismatch are expected to modify the physical properties of CrN relative to the bulk material. Indeed, variable-angle spectroscopic ellipsometry in the photon-energy range from 1.25 to 5 eV reveals a surprisingly strong polarization dependence of the optical response despite the nearly strain-free cubic crystal structure of the films. The pseudo-optical constants n and k differ by more than 10% for orthogonal in-plane polarizations throughout the investigated spectral range. We evaluate possible origins of this effect and conclude that it most likely arises from anisotropic surface morphology of CrN(113), which creates a metasurface acting as a subwavelength grating in the strongly absorbing regime.
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BibTeX
@misc{dinh2026large,
title = {{Large in-plane optical anisotropy in epitaxial CrN(113) films}},
author = {Duc V. Dinh and Frank Peiris and Oliver Brandt},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21856},
eprint = {2610.21856},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21856},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Large in-plane optical anisotropy in epitaxial CrN(113) films
AU - Duc V. Dinh
AU - Frank Peiris
AU - Oliver Brandt
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21856
UR - https://arxiv.org/abs/2610.21856
AB - CrN, a transition-metal nitride crystallizing in the cubic rocksalt structure, exhibits a unique combination of mechanical robustness, semiconducting behavior, and thermoelectric functionality. To date, however, CrN has been synthesized primarily as polycrystalline material or as epitaxial films grown along high-symmetry orientations such as (001) and (111). Here, we prepare epitaxial CrN(113) films on AlN(11\bar{2}2) templates by plasma-assisted molecular beam epitaxy. The low-symmetry interface and highly direction dependent lattice mismatch are expected to modify the physical properties of CrN relative to the bulk material. Indeed, variable-angle spectroscopic ellipsometry in the photon-energy range from 1.25 to 5 eV reveals a surprisingly strong polarization dependence of the optical response despite the nearly strain-free cubic crystal structure of the films. The pseudo-optical constants n and k differ by more than 10% for orthogonal in-plane polarizations throughout the investigated spectral range. We evaluate possible origins of this effect and conclude that it most likely arises from anisotropic surface morphology of CrN(113), which creates a metasurface acting as a subwavelength grating in the strongly absorbing regime.
ER -