Enhanced superconductivity by rare-earth metal doping in phenanthrene |
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| Authors: | X F Wang X G Luo J J Ying Z J Xiang S L Zhang R R Zhang Y H Zhang Y J Yan A F Wang P Cheng G J Ye X H Chen |
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| Institution: | Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China. |
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| Abstract: | We successfully synthesized La-?and Sm-doped phenanthrene powder samples and observed superconductivity in them at T(c) around 6?K. The T(c)s are 6.1?K for La(1) phenanthrene and 6.0?K for Sm(1) phenanthrene, which are enhanced by about 1 and 0.5?K compared to those in A(3) phenanthrene (A?=?K and Rb) and in Ae(1.5) phenanthrene (Ae?=?Sr and Ba) superconductors, respectively. The superconductive shielding fractions for La(1) phenanthrene and Sm(1) phenanthrene are 46.1% and 49.8% at 2?K, respectively. The small effect of doping with the magnetic ion Sm(3+) on T(c) and the positive pressure dependence coefficient of T(c) strongly suggest unconventional superconductivity in the doped phenanthrene superconductors. The charge transfer to organic molecules from dopants of La and Sm induces a redshift of 7?cm(-1) per electron for the mode at 1441?cm(-1) in the Raman spectra, which is almost the same as those observed in A(3) phenanthrene (A?=?K and Rb) and Ae(1.5) phenanthrene (Ae?=?Sr and Ba) superconductors. |
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