Magneto-THz spectroscopy in spinel superconductor LiTi2O4 thin films

We investigate a spinel superconductor, LiTi
₂
O
₄
using continues wave(CW) terahertz spectroscopy combined with THz TDS under magnetic fields. We observed a clear superconducting gap opening in about 0.4THz and a residual real part of the conductivity below the superconducting phase transition temperature, which indicates a pair-breaking effect. It was the first time that the superconducting gap was observed in the strong spin fluctuation compounds LiTi
₂
O
₄
by a continues wave terahertz spectroscopy.