Biomedical subjects
Publications and source records attributed to Hidenori Hiramatsu.
We report superconductivity in an iron-based layered oxy-pnictide LaOFeP. LaOFeP is composed of an alternate stack of lanthanum oxide (La3+O2-) and iron pnictide (Fe2+P3-) layers. Magnetic and electrical resistivity measurements verify the occurrence of the superconducting transition at approximately 4 K.
Degenerate four-wave mixing signals excited by femtosecond laser pulses were measured in LaCuOCh (Ch = S and Se) at 4 K. The signals for LaCuOS exhibit a beat structure with a period of 480 fs just at the exciton peak energy, indicating that the lowest exciton states are split by 9 meV, but no beat structure was observed in LaCuOSe, regardless of the laser's energy. The spin--orbit interaction of the Ch ion accompanied by the hybridization of Cu 3d orbitals causes splitting of the exciton levels. Furthermore, the contribution of Ch p orbitals in the valence band maximum is larger in LaCuOSe owing to increased covalency in the Cu--Ch bond when S is replaced with Se.