2015/02/25 by Mahmoud Abdel‐Hafiez, Abdel-Hafiez, Mahmoud, Zheng He +11
Business, Management and Accounting · Materials Science · #Corporate Taxation and Avoidance #FOS: Physical sciences #Iron-based superconductors research #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.1502.07130
openalex publication_date 2015/02/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
One of the major themes in the physics of condensed matter is unconventional superconductivity in correlated electronic systems. The symmetry structure of Cooper pairs is thought to be the key to the understanding of the pairing mechanism of their superconductivity. In iron pnictide superconductors, the precise symmetry of the order parameter as well its evolution with doping remains highly controversial. There is no general consensus on the nature of pairing in iron-based superconductors leaving the perspectives ranging from s++ wave, to s±, and d wave. Here we show that doping induced a sudden change of the pairing symmetry from the s++- to d-wave in the BaFe2-xNixAs2 system with an s± state near the crossover boundary at x=0.15. The presence of the s± state is of particular scientific interest because an intermediate phase breaks the pairing symmetry when the s- and d-wave phases come together to interfere. For x 0.15, we find the temperature and magnetic-field contributions to the specific heat in T2 and √(H), respectively, indicating line nodes in the SC gap. These findings thus clarify the symmetry nature as well as the evolution of the SC order parameter with doping in pnictide superconductors.