Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method

Abstract We investigated a high-quality MgB2 thin film with a thickness of ~1000 nm on an Al2O3 substrate using optical spectroscopy. We measured the reflectance spectra of the film at various temperatures both below, and above, the superconducting transition temperature, T c $$\simeq $$ ≃ 40 K....

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Yu-Seong Seo, Jae Hak Lee, Won Nam Kang, Jungseek Hwang
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/a0b8c54900e34dbc938ee32d3d64786f
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:a0b8c54900e34dbc938ee32d3d64786f
record_format	dspace
spelling	oai:doaj.org-article:a0b8c54900e34dbc938ee32d3d64786f2021-12-02T12:32:42ZRevisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method10.1038/s41598-017-09248-42045-2322https://doaj.org/article/a0b8c54900e34dbc938ee32d3d64786f2017-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-09248-4https://doaj.org/toc/2045-2322Abstract We investigated a high-quality MgB2 thin film with a thickness of ~1000 nm on an Al2O3 substrate using optical spectroscopy. We measured the reflectance spectra of the film at various temperatures both below, and above, the superconducting transition temperature, T c $$\simeq $$ ≃ 40 K. An earlier study showed that when the sample surface is exposed to air the optical properties of the surface change immediately, however, the saturated change is negligibly small in the far-infrared region. The optical conductivity spectrum in the normal state shows two (narrow and broad) Drude modes, with the narrow Drude mode being dominant in the low frequency region below 1000 cm−1. Our study, which uses a good-quality sample, provides more reliable data on the optical properties of MgB2, in a similar spectral range. The optical data is analyzed further using an extended Drude model, and the electron-phonon spectral density function, α 2 F(ω), is extracted. The spectral density function α 2 F(ω) features two peaks: a small one near 114 cm−1, and a strong peak around the 550 cm−1 where the B-B bond stretching phonon exists. Our data in the superconducting state does not show the expected energy shift of the onset of scattering associated with the α 2 F(ω) peaks.Yu-Seong SeoJae Hak LeeWon Nam KangJungseek HwangNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-8 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Yu-Seong Seo Jae Hak Lee Won Nam Kang Jungseek Hwang Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method
description	Abstract We investigated a high-quality MgB2 thin film with a thickness of ~1000 nm on an Al2O3 substrate using optical spectroscopy. We measured the reflectance spectra of the film at various temperatures both below, and above, the superconducting transition temperature, T c $$\simeq $$ ≃ 40 K. An earlier study showed that when the sample surface is exposed to air the optical properties of the surface change immediately, however, the saturated change is negligibly small in the far-infrared region. The optical conductivity spectrum in the normal state shows two (narrow and broad) Drude modes, with the narrow Drude mode being dominant in the low frequency region below 1000 cm−1. Our study, which uses a good-quality sample, provides more reliable data on the optical properties of MgB2, in a similar spectral range. The optical data is analyzed further using an extended Drude model, and the electron-phonon spectral density function, α 2 F(ω), is extracted. The spectral density function α 2 F(ω) features two peaks: a small one near 114 cm−1, and a strong peak around the 550 cm−1 where the B-B bond stretching phonon exists. Our data in the superconducting state does not show the expected energy shift of the onset of scattering associated with the α 2 F(ω) peaks.
format	article
author	Yu-Seong Seo Jae Hak Lee Won Nam Kang Jungseek Hwang
author_facet	Yu-Seong Seo Jae Hak Lee Won Nam Kang Jungseek Hwang
author_sort	Yu-Seong Seo
title	Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method
title_short	Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method
title_full	Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method
title_fullStr	Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method
title_full_unstemmed	Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method
title_sort	revisiting optical properties of mgb2 with a high-quality sample prepared by a hpcvd method
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/a0b8c54900e34dbc938ee32d3d64786f
work_keys_str_mv	AT yuseongseo revisitingopticalpropertiesofmgb2withahighqualitysamplepreparedbyahpcvdmethod AT jaehaklee revisitingopticalpropertiesofmgb2withahighqualitysamplepreparedbyahpcvdmethod AT wonnamkang revisitingopticalpropertiesofmgb2withahighqualitysamplepreparedbyahpcvdmethod AT jungseekhwang revisitingopticalpropertiesofmgb2withahighqualitysamplepreparedbyahpcvdmethod
_version_	1718393996168921088

Revisiting optical properties of MgB2 with a high-quality sample prepared by a HPCVD method

Ejemplares similares