Direct observation of charge re-distribution in a MgB2 superconductor

To study the origin of negative thermal expansion effects near the superconducting transition temperature TC in MgB2, low-temperature high-energy synchrotron radiation x-ray diffraction was used to probe the charge redistribution near the boron atoms. Our results reveal that the in-plane hole-distri...

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Bibliographic Details
Published inSuperconductor science & technology Vol. 29; no. 4
Main Authors Wu, Sheng Yun, Shih, Po-Hsun, Ji, Jhong-Yi, Chan, Ting-Shan, Yang, Chun Chuen
Format Journal Article
LanguageEnglish
Published IOP Publishing 22.02.2016
Subjects
negative thermal expansion
superconductivity
two-phonon effect
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Summary:To study the origin of negative thermal expansion effects near the superconducting transition temperature TC in MgB2, low-temperature high-energy synchrotron radiation x-ray diffraction was used to probe the charge redistribution near the boron atoms. Our results reveal that the in-plane hole-distribution of B− hops through the direct orbital overlap of Mg2+ along the c-axis at 50 K and is re-distributed out-of-plane. This study shows that the out-of-plane π-hole distribution plays a dominant role in the possible origin of superconductivity and negative thermal effects in MgB2.
Bibliography:SUST-101389.R2
ISSN:0953-2048
1361-6668
DOI:10.1088/0953-2048/29/4/045001