%0 Journal Article
%T Natural optical anisotropy of h-BN: Highest giant birefringence in a bulk crystal through the mid-infrared to ultraviolet range
%+ Institut Universitari de Ciencia dels Materials (ICMUV)
%+ Institute of Earth Sciences Jaume Almera
%+ National Institute for Materials Science (NIMS)
%+ Laboratoire Charles Coulomb (L2C)
%A Segura, A
%A Artus, L.
%A Cusco, R.
%A Taniguchi, Takashi
%A Cassabois, Guillaume
%A Gil, Bernard
%< avec comité de lecture
%Z L2C:18-016
%@ 2475-9953
%J Physical Review Materials
%I American Physical Society
%V 2
%P 024001
%8 2018-02-19
%D 2018
%R 10.1103/PhysRevMaterials.2.024001
%K Boron nitride
%K Van der waals interactions
%K 2D materials
%K wide bandgap
%K semiconductors
%Z Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other]
%Z Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Journal articles
%X The giant birefringence of layered h-BN was demonstrated by analyzing the interference patterns in reflectance and transmittance measurements in the mid-infrared to the deep ultraviolet energy range. The refractive index for polarization perpendicular to the c axis is much higher than the refractive index for polarization parallel to the c axis, and it displays a strong increase in the ultraviolet range that is attributed to the huge excitonic effects arising from the unique electronic structure of h-BN. Thus, h-BN is shown to exhibit a giant negative birefringence that ranges from −0.7 in the visible to −2 in the deep ultraviolet close to the band gap. The electronic dielectric constants for polarization perpendicular and parallel to the c axis were determined to be ε∞⊥ = 4.95 and ε∞∥ = 2.86, respectively. The anisotropy we find in high-quality h-BN is significantly larger than proposed in previous experimental studies but in excellent agreement with ab initio calculations.
%G English
%2 https://hal.science/hal-01712338/document
%2 https://hal.science/hal-01712338/file/Artus_PHYSICAL_REVIEW_MATERIALS_2_024001.pdf
%L hal-01712338
%U https://hal.science/hal-01712338
%~ CNRS
%~ L2C
%~ MIPS
%~ UNIV-MONTPELLIER
%~ UM-2015-2021