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Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)

Copper metaborate had a unique crystal structure and exhibited noteworthy magnetic phase transitions at 21 and 10 K. The electronic structure and lattice dynamics of copper metaborate Cu(11)B(2)O(4) single crystals were investigated and compared with the optical properties of CuB(2)O(4), to assess t...

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Autores principales: Mero, Rea Divina, Lai, Chun-Hao, Du, Chao-Hung, Liu, Hsiang-Lin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9057853/
https://www.ncbi.nlm.nih.gov/pubmed/35516545
http://dx.doi.org/10.1039/d0ra08200g
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author Mero, Rea Divina
Lai, Chun-Hao
Du, Chao-Hung
Liu, Hsiang-Lin
author_facet Mero, Rea Divina
Lai, Chun-Hao
Du, Chao-Hung
Liu, Hsiang-Lin
author_sort Mero, Rea Divina
collection PubMed
description Copper metaborate had a unique crystal structure and exhibited noteworthy magnetic phase transitions at 21 and 10 K. The electronic structure and lattice dynamics of copper metaborate Cu(11)B(2)O(4) single crystals were investigated and compared with the optical properties of CuB(2)O(4), to assess the boron isotope effect. The optical absorption spectrum at room temperature revealed two charge-transfer bands at approximately 4.30 and 5.21 eV with an extrapolated direct optical band gap of 3.16 ± 0.07 eV. Compared with the data on CuB(2)O(4), the electronic transitions were shifted to lower energies upon the replacement of a heavier boron isotope. The band gap was also determined to be lower in Cu(11)B(2)O(4). Anomalies in the temperature dependence of the optical band gap were observed below 21 K. Furthermore, 38 Raman-active phonon modes were identified in the room-temperature Raman scattering spectrum of Cu(11)B(2)O(4), which were also observed in CuB(2)O(4) with a shift to lower frequencies. No broadening caused by isotopic changes was observed. As the temperature decreased, phonon frequencies shifted to higher wavenumbers and the linewidth decreased. Anomalous softening in the Raman peaks below 21 K was also revealed.
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spelling pubmed-90578532022-05-04 Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4) Mero, Rea Divina Lai, Chun-Hao Du, Chao-Hung Liu, Hsiang-Lin RSC Adv Chemistry Copper metaborate had a unique crystal structure and exhibited noteworthy magnetic phase transitions at 21 and 10 K. The electronic structure and lattice dynamics of copper metaborate Cu(11)B(2)O(4) single crystals were investigated and compared with the optical properties of CuB(2)O(4), to assess the boron isotope effect. The optical absorption spectrum at room temperature revealed two charge-transfer bands at approximately 4.30 and 5.21 eV with an extrapolated direct optical band gap of 3.16 ± 0.07 eV. Compared with the data on CuB(2)O(4), the electronic transitions were shifted to lower energies upon the replacement of a heavier boron isotope. The band gap was also determined to be lower in Cu(11)B(2)O(4). Anomalies in the temperature dependence of the optical band gap were observed below 21 K. Furthermore, 38 Raman-active phonon modes were identified in the room-temperature Raman scattering spectrum of Cu(11)B(2)O(4), which were also observed in CuB(2)O(4) with a shift to lower frequencies. No broadening caused by isotopic changes was observed. As the temperature decreased, phonon frequencies shifted to higher wavenumbers and the linewidth decreased. Anomalous softening in the Raman peaks below 21 K was also revealed. The Royal Society of Chemistry 2020-11-17 /pmc/articles/PMC9057853/ /pubmed/35516545 http://dx.doi.org/10.1039/d0ra08200g Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/
spellingShingle Chemistry
Mero, Rea Divina
Lai, Chun-Hao
Du, Chao-Hung
Liu, Hsiang-Lin
Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)
title Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)
title_full Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)
title_fullStr Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)
title_full_unstemmed Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)
title_short Anomalous boron isotope effects on electronic structure and lattice dynamics of CuB(2)O(4)
title_sort anomalous boron isotope effects on electronic structure and lattice dynamics of cub(2)o(4)
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9057853/
https://www.ncbi.nlm.nih.gov/pubmed/35516545
http://dx.doi.org/10.1039/d0ra08200g
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