摘要： 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. 其他題名： SUST 其他題名： Supercond. Sci. Technol 出版者： IOP Publishing 出版日期： 2016-02-22 出處： Superconductor science & technology, 2016-02, Vol.29 (4) 資源來源： Institute of Physics Journals 版權： 2016 IOP Publishing Ltd 識別號： ISSN: 0953-2048 識別號： EISSN: 1361-6668 識別號： DOI: 10.1088/0953-2048/29/4/045001 識別號： CODEN: SUSTEF
