Dr. Tingyong Chen
Department of Physics, Arizona State University, Tempe 85287, USA
时间: 5月25日 下午2:00
地点:唐仲英楼B501室
Electrons pair with opposite spin orientations in a singlet superconductor such as an s- and d- wave superconductors, yet they can also pair with the same spin direction in a triplet superconductor such as a p-wave superconductor. Triplet superconductivity has been proposed since the Bardeen-Cooper-Schrieffer (BCS) theory and many superconductors have been predicted to be triplet, including the recent Fe-superconductors. However, an unambiguous triplet superconductor is still elusive because it is experimentally nontrivial to differentiate a triplet superconductor from a singlet superconductor. At a superconductor/normal metal interface when an electron is injected into the superconductor, it must carry another electron with appropriate spin to form a Cooper pair. A half-metallic current cannot be injected into a singlet superconductor because of the absence of the opposite spins, but it can be injected into a triplet superconductor where electrons can have the same spin directions. Using this technique, we conclusively show that the Fe-superconductor SmO0.82F0.18FeAs, which has been predicted to be p-wave, is a single superconductor. Instead, I will show a very promising p-wave candidate.