Content of SPECIAL TOPIC—Unconventional superconductivity in our journal

Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select Dispersion of neutron spin resonance mode in Ba0.67K0.33Fe2As2 Tao Xie(谢涛), Chang Liu(刘畅), Tom Fennell, Uwe Stuhr, Shi-Liang Li(李世亮), and Hui-Qian Luo(罗会仟) Chin. Phys. B, 2021, 30 (12): 127402.   DOI: 10.1088/1674-1056/ac3651 Abstract （399）   HTML （5）    PDF （1676KB）（158）       Knowledge map    We report an inelastic neutron scattering investigation on the spin resonance mode in the optimally hole-doped iron-based superconductor Ba0.67K0.33Fe2As2 with Tc=38.2 K. Although the resonance is nearly two-dimensional with peak energy ER≈14 meV, it splits into two incommensurate peaks along the longitudinal direction ([H, 0, 0]) and shows an upward dispersion persisting to 26 meV. Such dispersion breaks through the limit of total superconducting gaps ∆tot=|∆k|+|∆k+Q|(about 11-17 meV) on nested Fermi surfaces measured by high resolution angle resolved photoemission spectroscopy (ARPES). These results cannot be fully understood by the magnetic exciton scenario under s±-pairing symmetry of superconductivity, and suggest that the spin resonance may not be restricted by the superconducting gaps in the multi-band systems. Select Tip-induced superconductivity commonly existing in the family of transition-metal dipnictides MPn2 Meng-Di Zhang(张孟迪), Sheng Xu(徐升), Xing-Yuan Hou(侯兴元), Ya-Dong Gu(谷亚东), Fan Zhang(张凡), Tian-Long Xia(夏天龙), Zhi-An Ren(任治安), Gen-Fu Chen(陈根富), Ning Hao(郝宁), and Lei Shan(单磊) Chin. Phys. B, 2021, 30 (1): 017304.   DOI: 10.1088/1674-1056/abccbb Abstract （461）   HTML （11）    PDF （1255KB）（204）       Knowledge map    We report the tip-induced superconductivity on the topological semimetal NbSb2, similar to the observation on TaAs2 and NbAs2. Belonging to the same family of MPn2, all these materials possess similar band structures, indicating that the tip-induced superconductivity may be closely related to their topological nature and share a common mechanism. Further analysis suggests that a bulk band should play the dominant role in such local superconductivity most likely through interface coupling. In addition, the compatibility between the induced superconductivity and tips' ferromagnetism gives an evidence for its unconventional nature. These results provide further clues to elucidate the mechanism of the tip-induced superconductivity observed in topological materials. Select Theory of unconventional superconductivity in nickelate-based materials Ming Zhang(张铭), Yu Zhang(张渝), Huaiming Guo(郭怀明), and Fan Yang(杨帆) Chin. Phys. B, 2021, 30 (10): 108204.   DOI: 10.1088/1674-1056/ac0bb1 Abstract （416）   HTML （8）    PDF （4986KB）（251）       Knowledge map    Based on the two-band tight-binding model composed of the 3d orbital of Ni and the 5d orbital of R (=La), we used the random-phase-approximation method to study the pairing symmetry of the nickelate superconductors. It is found that even without considering the coupling between the R and Ni orbitals, neither the antiferromagnetic spin-fluctuation pattern nor the doping-dependent behavior of the robust dx2-y2-wave pairing state obtained in our calculations will be obviously influenced. Our results suggest the dominating role of the Ni 3d orbital in determining the low lying physics of the system. Furthermore, our results reveal a dome-shaped doping dependence of the superconducting transition temperature Tc, which is consistent with recent experiments.