Ultrafast observation of the coexistence of antiferromagnetism and superconductivity in a High-Tc superconductor

Ultrafast quasiparticle dynamics of the high-Tc superconductor Tl2Ba2Ca2CU3Oy were probed using the all-optical pump-probe technique. Our results are consistent with the coexistence of antiferromagnetism and superconductivity at low temperatures, resulting in the depression of the superconducting gap and the opening of a spin-density-wave gap.